Migrate MediaSessionComponent to android 13.
This was primarily implementing custom actions with the media session
and adding some extra bug fixes that I was already planning. I was
really hoping that google fixes the nightmarish mess that was the
previous MediaStyle notification, where I had to update the session
and then the notification in a tight dance with clever tricks to not
get rate-limited, but nope. I still have to do exactly the same thing
as beforehand, but with even extra insanity due to the custom actions.
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