Android studio flutter plugin should use --config-only when opening example app in plugin

### Is there an existing issue for this?

- [X] I have searched the [existing issues](https://github.com/flutter/flutter/issues)
- [X] I have read the [guide to filing a bug](https://flutter.dev/docs/resources/bug-reports)

### Use case

https://github.com/flutter/flutter/issues/19830 Is an issue with 85 upvotes where users are confused about how they can get their code to link correctly in android studio. We also have a documentation update task but this request is to avoid a common error.

Plugins are not buildable on their own so users already need to take the unintuitive step to open the example app we suggest in each plugin. The problem with that is we generate files on demand during a `flutter run` or `flutter build` that are required for android studio to know how to link the source.

--config-only is a build step we added to generate the gradle files required.

### Proposal

Modify the flutter android studio plugin to mitigate this class of errors for users by either building or running config-only for them.

This is important despite the migration to vs code as our suggested editor because we still tell plugin developers working on android or add to app developers to use android studio.