Simplify #1836 fix, Avoid map-related casting errors in project factory

blueprints/factories/project-factory/factory.tf

@@ -15,18 +15,17 @@
  */
 
 locals {
-  # turn the set of file names into a list for index-based access later on
-  _factory_files = [
-    for f in fileset("${pathexpand(var.factory_data_path)}", "**/*.yaml") : f
-  ]
-  # use a list to store data to avoid map enforcing the same type for all
-  _factory_data = [
-    for f in local._factory_files :
-    yamldecode(file("${pathexpand(var.factory_data_path)}/${f}"))
-  ]
-  # assemble final data, emulating optionals and using defaults and merges
+  _data = (
+    {
+      for f in fileset(local._data_path, "**/*.yaml") :
+      trimsuffix(f, ".yaml") => yamldecode(file("${local._data_path}/${f}"))
+    }
+  )
+  _data_path = var.factory_data_path == null ? null : pathexpand(
+    var.factory_data_path
+  )
   projects = {
-    for i, v in local._factory_data : trimsuffix(local._factory_files[i], ".yaml") => {
+    for k, v in local._data : k => merge(v, {
       billing_account = try(coalesce(
         var.data_overrides.billing_account,
         try(v.billing_account, null),
@@ -95,7 +94,7 @@ locals {
         try(v.service_accounts, null),
         var.data_defaults.service_accounts
       )
-    }
+    })
   }
   service_accounts = flatten([
     for k, v in local.projects : [