[amplify_analytics_pinpoint] AGP 9 incompatibility — kotlin-android plugin must be removed

See same problem with solution in firebase plugins: https://github.com/firebase/flutterfire/issues/17987
```
A problem occurred evaluating project ':amplify_analytics_pinpoint'.
> Failed to apply plugin 'kotlin-android'.
   > Cannot add extension with name 'kotlin', as there is an extension already registered with that name.
```