TensorFlow Lite BERT QA Android app Update SDK > 35

[Chris-Hamid]

This PR updates the TensorFlow Lite BERT QA Android app to support modern Android SDKs:

• Upgraded to Gradle 8.7, AGP 8.5.0, Kotlin 1.9.20.
• Updated compileSdk and targetSdk to 35.
• Tested on API 36 Beta (Pixel 9 XL virtual emulator).
• Added CONTRIBUTING.md in lite/examples/bert_qa/android with detailed instructions and guidelines.

These changes ensure the app remains compatible with the latest Android versions while maintaining functionality.

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[Chris-Hamid]

@googlebot recheck cla