move mediaplayer releasing back on main thread

app/src/main/kotlin/com/simplemobiletools/gallery/fragments/VideoFragment.kt

@@ -467,11 +467,9 @@ class VideoFragment : ViewPagerFragment(), SurfaceHolder.Callback, SeekBar.OnSee
     }
 
     private fun releaseMediaPlayer() {
-        Thread {
         mMediaPlayer?.setSurface(null)
         mMediaPlayer?.release()
         mMediaPlayer = null
-        }.start()
     }
 
     private fun videoPrepared(mediaPlayer: MediaPlayer) {