Keep those MediaControllers of none addressed players to be up-to-date

We moniter both changes of session and player from MediaSessionManager
and only update the MediaController of activated player. In case if
session changes serveral times before player activated, the old
MediaController would be deprecated but still was in used.  Without
session changed again to update the MediaController, it causes AVRCP
can't receive callbacks from MediaSessionManager after player activated.

We now always update the MediaController to new one no matter the
player is activated or not so can receive player's callbacks as well.

Bug: 110408992
Bug: 111622139
Test: manually switching players
Change-Id: Idfa144f68743679613f4e11f8cd75dd889f01f0e
Merged-In: Idfa144f68743679613f4e11f8cd75dd889f01f0e
(cherry picked from commit 105d3bd0)