[#594] Don't Allow user to proceed to send funds if they are not available for spend (#629)

- send button disable/enable logic
- `clear` button of the address field removed

secant/Features/SendFlow/Views/CreateTransactionView.swift

@@ -48,6 +48,8 @@ struct CreateTransaction: View {
                     label: { Text(L10n.General.send) }
                 )
                 .activeButtonStyle
+                .disabled(viewStore.isValidForm)
+                .opacity(viewStore.isValidForm ? 1.0 : 0.5)
 
                 Spacer()
             }

secant/UI Components/TextFields/TransactionAddress/TransactionAddressTextField.swift

@@ -21,20 +21,8 @@ struct TransactionAddressTextField: View {
                         state: \.textFieldState,
                         action: TransactionAddressTextFieldReducer.Action.textField
                     ),
-                    titleAccessoryView: {
-                        if !viewStore.textFieldState.text.data.isEmpty {
-                            Button(
-                                action: {
-                                    viewStore.send(.clearAddress)
-                                },
-                                label: {
-                                    Text(L10n.General.clear)
-                                }
-                            )
-                            .textFieldTitleAccessoryButtonStyle
-                        }
-                    },
-                    inputPrefixView: { EmptyView() },
+                    titleAccessoryView: { },
+                    inputPrefixView: { },
                     inputAccessoryView: {
                         Button {
                             viewStore.send(.scanQR)