Disconnect MediaBrowserWrapper after every operation

Instead of trying to keep Browsable Players in a conected state whenever
possible, disconnect them immediatly after every opperation in order to
prevent them from keeping a high priority.

Bug: 78787396
Test: "adb shell dumpsys activity" and see that browsable players don't
have thier priorities bumped.
Change-Id: I66eede99fe256676ef64596f73aed00d7142f8f7