Fix AudoFocus pausing video when attempting to play

[armands-malejevs]

Fix AudioFocus bug that could cause the player to stop responding to play/pause in some instances.

Fixes issue #1945

This was caused by the player requesting audio focus on each play (un-pause) and that resulted in a small window of Audio focus loss and then gain. The focus loss results in the player being paused while the player was supposed to play at the time. The solution is to keep track of Audio focus and not request new focus if we already have it.

[deepak-jha-kgp]

Hi @armadilio3 Do you think this could be a reason for #2312 as well?

[armands-malejevs]

@deepak-jha-kgp It's possible that the lower end devices don't handle focus loss/gain very quickly and could start stuttering. Looking at the video the symptoms seem to be similar so its possible that this would fix the issue, but the only way to make sure would be using the player with these changes included and checking if its still reproducible.

[deepak-jha-kgp]

Thank you @armadilio3. I will implement this and get back to you

[t-fritsch]

Tested with RN 0.64 + react-native-video-controls 2.7.1 and this PR seems to work just fine.
Thanks a lot

[ajayAloha]

Hi @armadilio3 Thanks a ton for fixing this. I have wasted a day trying to figure out the issue. :)