chore: group ORM audit changes (#11842)

## Description

ref: #10968 



---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/main/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/main/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/main/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

x/group/internal/orm/genesis.go

@@ -4,7 +4,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
-// TableExportable
+// TableExportable defines the methods to import and export a table.
 type TableExportable interface {
 	// Export stores all the values in the table in the passed
 	// ModelSlicePtr. If the table has an associated sequence, then its

x/group/internal/orm/index.go

@@ -132,18 +132,11 @@ func (i MultiKeyIndex) GetPaginated(store sdk.KVStore, searchKey interface{}, pa
 //
 // CONTRACT: No writes may happen within a domain while an iterator exists over it.
 func (i MultiKeyIndex) PrefixScan(store sdk.KVStore, startI interface{}, endI interface{}) (Iterator, error) {
-	start, err := getPrefixScanKeyBytes(startI)
-	if err != nil {
-		return nil, err
-	}
-	end, err := getPrefixScanKeyBytes(endI)
+	start, end, err := getStartEndBz(startI, endI)
 	if err != nil {
 		return nil, err
 	}
 
-	if start != nil && end != nil && bytes.Compare(start, end) >= 0 {
-		return NewInvalidIterator(), sdkerrors.Wrap(errors.ErrORMInvalidArgument, "start must be less than end")
-	}
 	pStore := prefix.NewStore(store, []byte{i.prefix})
 	it := pStore.Iterator(start, end)
 	return indexIterator{store: store, it: it, rowGetter: i.rowGetter, indexKey: i.indexKey}, nil
@@ -159,23 +152,35 @@ func (i MultiKeyIndex) PrefixScan(store sdk.KVStore, startI interface{}, endI in
 //
 // CONTRACT: No writes may happen within a domain while an iterator exists over it.
 func (i MultiKeyIndex) ReversePrefixScan(store sdk.KVStore, startI interface{}, endI interface{}) (Iterator, error) {
-	start, err := getPrefixScanKeyBytes(startI)
-	if err != nil {
-		return nil, err
-	}
-	end, err := getPrefixScanKeyBytes(endI)
+	start, end, err := getStartEndBz(startI, endI)
 	if err != nil {
 		return nil, err
 	}
 
-	if start != nil && end != nil && bytes.Compare(start, end) >= 0 {
-		return NewInvalidIterator(), sdkerrors.Wrap(errors.ErrORMInvalidArgument, "start must be less than end")
-	}
 	pStore := prefix.NewStore(store, []byte{i.prefix})
 	it := pStore.ReverseIterator(start, end)
 	return indexIterator{store: store, it: it, rowGetter: i.rowGetter, indexKey: i.indexKey}, nil
 }
 
+// getStartEndBz gets the start and end bytes to be passed into the SDK store
+// iterator.
+func getStartEndBz(startI interface{}, endI interface{}) ([]byte, []byte, error) {
+	start, err := getPrefixScanKeyBytes(startI)
+	if err != nil {
+		return nil, nil, err
+	}
+	end, err := getPrefixScanKeyBytes(endI)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if start != nil && end != nil && bytes.Compare(start, end) >= 0 {
+		return nil, nil, sdkerrors.Wrap(errors.ErrORMInvalidArgument, "start must be less than end")
+	}
+
+	return start, end, nil
+}
+
 func getPrefixScanKeyBytes(keyI interface{}) ([]byte, error) {
 	var (
 		key []byte

x/group/internal/orm/primary_key.go

@@ -33,9 +33,9 @@ type PrimaryKeyed interface {
 	// the primary key. The PrimaryKey function will encode and concatenate
 	// the fields to build the primary key.
 	//
-	// PrimaryKey parts can be []byte, string, and integer types. []byte is
+	// PrimaryKey parts can be []byte, string, and uint64 types. []byte is
 	// encoded with a length prefix, strings are null-terminated, and
-	// integers are encoded using 8 byte big endian.
+	// uint64 are encoded using 8 byte big endian.
 	//
 	// IMPORTANT: []byte parts are encoded with a single byte length prefix,
 	// so cannot be longer than 255 bytes.

x/group/internal/orm/spec/01_table.md

@@ -9,10 +9,11 @@ Regular CRUD operations can be performed on a table, these methods take a `sdk.K
 
 The `table` struct does not:
 
-* enforce uniqueness of the `RowID`
-* enforce prefix uniqueness of keys, i.e. not allowing one key to be a prefix
- of another
-* optimize Gas usage conditions
+- enforce uniqueness of the `RowID`
+- enforce prefix uniqueness of keys, i.e. not allowing one key to be a prefix
+  of another
+- optimize Gas usage conditions
+
 The `table` struct is private, so that we only have custom tables built on top of it, that do satisfy these requirements.
 
 `table` provides methods for exporting (using a [`PrefixScan` `Iterator`](03_iterator_pagination.md#iterator)) and importing genesis data. For the import to be successful, objects have to be aware of their primary key by implementing the [`PrimaryKeyed`](#primarykeyed) interface.
@@ -42,6 +43,6 @@ The primary key parts can be []byte, string, and `uint64` types.
 
 Key parts, except the last part, follow these rules:
 
-* []byte is encoded with a single byte length prefix
-* strings are null-terminated
-* `uint64` are encoded using 8 byte big endian.
+- []byte is encoded with a single byte length prefix (which means the max []byte length is 255)
+- strings are null-terminated
+- `uint64` are encoded using 8 byte big endian.