cleanup: Remove unused Java_MediaCodecBridge_start

[borongc]

Remove the MediaCodecBridge.start() method, previously callable
from native code. This method is no longer invoked from the native
Cobalt codebase and is thus unused. Removing it reduces code
footprint and potential for future confusion or errors.

gen/jni_headers/cobalt/android/jni_headers/MediaCodecBridge_jni.h:407:17: warning: unused function 'Java_MediaCodecBridge_start' [-Wunused-function]
  407 | static jboolean Java_MediaCodecBridge_start(JNIEnv* env, const jni_zero::JavaRef<jobject>& obj) {
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.

Issue: 484411174

[github-actions]

🤖 Gemini Suggested Commit Message

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android: Remove unused MediaCodecBridge.start()

Remove the MediaCodecBridge.start() method, previously callable
from native code. This method is no longer invoked from the native
Cobalt codebase and is thus unused. Removing it reduces code
footprint and potential for future confusion or errors.

Bug: 484411174

---

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[gemini-code-assist]

Code Review

This pull request is a good cleanup, removing an unused @CalledByNative annotation, which will stop the generation of an unnecessary JNI function. I've added one suggestion for a potential further cleanup: if the start() method is now completely unused, it could be removed entirely.