Fix TextFieldState restoration on iOS

[HarukeyUA]

When experimenting with implementing state restoration on iOS with custom SaveableStateRegistry I ran into a crash when trying to restore TextFieldState using its default saver.

Uncaught Kotlin exception: kotlin.ClassCastException: class kotlin.collections.ArrayList cannot       
  be cast to class kotlin.Int                                                                           
      at 0   KotlinProject.debug.dylib           0x10524ceeb                                            
  kfun:kotlin.Throwable#<init>(kotlin.String?){} + 99                                                   
      at 1   KotlinProject.debug.dylib           0x1052472d3                                            
  kfun:kotlin.Exception#<init>(kotlin.String?){} + 95                                                   
      at 2   KotlinProject.debug.dylib           0x105247493                                            
  kfun:kotlin.RuntimeException#<init>(kotlin.String?){} + 95                                            
      at 3   KotlinProject.debug.dylib           0x105247c03                                            
  kfun:kotlin.ClassCastException#<init>(kotlin.String?){} + 95                                          
      at 4   KotlinProject.debug.dylib           0x10527d3bb        ThrowClassCastException + 627       
      at 5   KotlinProject.debug.dylib           0x105effbeb                                            
  kfun:androidx.compose.foundation.text.input.TextUndoManager.Companion.Saver.TextUndoManager$Compa     
  nion$Saver$inlined$createSaver$1.restore#internal + 1471                                              
      at 6   KotlinProject.debug.dylib           0x10584db07                                            
  kfun:androidx.compose.runtime.saveable.Saver#restore(1:1){}1:0?-trampoline + 107                      
      at 7   KotlinProject.debug.dylib           0x105efebc7                                            
  kfun:androidx.compose.foundation.text.input.TextUndoManager.Companion.Saver#restore(kotlin.Any){}     
  androidx.compose.foundation.text.input.TextUndoManager? + 1539                                        
      at 8   KotlinProject.debug.dylib           0x105efb14f                                            
  kfun:androidx.compose.foundation.text.input.TextFieldState.Saver#restore(kotlin.Any){}androidx.co     
  mpose.foundation.text.input.TextFieldState? + 1367                                                    
      at 9   KotlinProject.debug.dylib           0x10584db07                                            
  kfun:androidx.compose.runtime.saveable.Saver#restore(1:1){}1:0?-trampoline + 107 

I've tracked the issue down to how UndoManager restores its state by using destructive declaration casting the whole List<Any> to List<Int> and reading from it. This works fine on Android and Jvm but crashes on iOS and, I presume, other Kotlin/Native targets.

The fix is to replace the destructive declaration and list cast with direct access by index.

Testing

• Clone the project's https://github.com/HarukeyUA/kmp-architecture-template text-field-state-restoration-crash branch
• Run the iOS app, click login, tap on the "Search" in the bottom navigation and enter any text in the text field
• Dismiss the app from the resents and relaunch the app. The app crashes when trying to restore the field's state
• Apply the fix, build CMP with the fix, point the test app to the maven local version and retest the scenario - app no longer crashes and state is correctly restored

Release Notes

Fixes - iOS

• Fix TextFieldState.Saver restoration crash

Google CLA

Signed