Fix Exoplayer Memory Leak

[SuhasDissa]

Fixed a bug that caused created multiple ExoPlayer instances during each Screen composition. (Cause the phone to freeze if I keep the video view open for too long)

Its quite hard to see the problem. Problem becomes more noticeable when using exoPlayer.play() which plays the video in background but doesn't update the UI. (obviously because it affects a separate invisible instance of the player) and also exoPlayer.stop() doesn't actually stop the playing video.

[Bnyro]

Thank you! <3

[SuhasDissa]

Sorry for the previous bad PR. I was debugging the issue the whole day and my repo clone was not in a good state for a commit. So i just edited the code with GitHub web UI And forgot to add the import statement.

Pardon the inconvenience caused.

[Bnyro]

No worries :)