[video_player_android] isBuffering flag always return true after calling seekTo method - fixed (#9198)

fixes  [Issue #165149](flutter/flutter#165149) 

## Pre-Review Checklist

### Root Cause

The issue stems from the `onPlaybackStateChanged` callback. After calling `seekTo`, the player transitions to `Player.STATE_BUFFERING`, setting the buffering flag to `true`. Shortly after, it transitions to `Player.STATE_READY`. However, if the player was already initialized, the method returned early due to:

```java
if (isInitialized) {
  return;
}
```

prevented `setBuffering(false)` from being called in the shared logic below the switch

Author: raju-muliyashiya

packages/video_player/video_player_android/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 2.8.6
+
+* Fixes a [bug](https://github.com/flutter/flutter/issues/165149) where the `isBuffering` flag
+  always returns true after seeking to any position.
+
 ## 2.8.5
 
 * Replaces deprecated `onSurfaceDestroyed` with `onSurfaceCleanup`.

packages/video_player/video_player_android/android/src/main/java/io/flutter/plugins/videoplayer/ExoPlayerEventListener.java

@@ -69,11 +69,10 @@ public void onPlaybackStateChanged(final int playbackState) {
         events.onBufferingUpdate(exoPlayer.getBufferedPosition());
         break;
       case Player.STATE_READY:
-        if (isInitialized) {
-          return;
+        if (!isInitialized) {
+          isInitialized = true;
+          sendInitialized();
         }
-        isInitialized = true;
-        sendInitialized();
         break;
       case Player.STATE_ENDED:
         events.onCompleted();

packages/video_player/video_player_android/android/src/test/java/io/flutter/plugins/videoplayer/ExoPlayerEventListenerTest.java

@@ -94,6 +94,19 @@ public void onPlaybackStateChangedEndedAfterBufferingSendsBufferingEndAndOnCompl
     verifyNoMoreInteractions(mockCallbacks);
   }
 
+  @Test
+  public void onPlaybackStateChangedReadyAfterBufferingSendsBufferingEnd() {
+    when(mockExoPlayer.getBufferedPosition()).thenReturn(10L);
+    eventListener.onPlaybackStateChanged(Player.STATE_BUFFERING);
+    verify(mockCallbacks).onBufferingStart();
+    verify(mockCallbacks).onBufferingUpdate(10L);
+
+    eventListener.onPlaybackStateChanged(Player.STATE_READY);
+    verify(mockCallbacks).onBufferingEnd();
+
+    verifyNoMoreInteractions(mockCallbacks);
+  }
+
   @Test
   public void onPlaybackStateChangedIdleDoNothing() {
     eventListener.onPlaybackStateChanged(Player.STATE_IDLE);

packages/video_player/video_player_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: video_player_android
 description: Android implementation of the video_player plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/video_player/video_player_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+video_player%22
-version: 2.8.5
+version: 2.8.6
 
 environment:
   sdk: ^3.7.0