Remove MessageQueueThreadHandler.java to fix CI (#49613)

Summary:
MessageQueueThreadHandler was migrated to Kotlin in https://github.com/facebook/react-native/pull/49583 but during merging the Java file was kept, this is currently breaking the `build-android` action in CI. [See this action for example](https://github.com/facebook/react-native/actions/runs/13472084782/job/37646841097?pr=49607)

## Changelog:

[INTERNAL] - Remove MessageQueueThreadHandler.java implementation to fix CI

Pull Request resolved: https://github.com/facebook/react-native/pull/49613

Test Plan:
```bash
yarn build-android
```

Reviewed By: fkgozali

Differential Revision: D70059045

Pulled By: arushikesarwani94

fbshipit-source-id: 93665a8ac4ccc1cb1b03908179e2fcd12c61b3dd