MediaSession2: Re-enable MediaSessionManager releated tests

Some tests were  previously disabled because the server didn't recognize
test apk installation. Re-enable those tests.

Some tests were broken while they had been hidden, and later CLs will
fix failures.

Bug: 72613128
Test: Run all MediaComponents tests. Following failures will be fixed
      in next CLs
        - MediaSessionmanager_MediaSession2
            #testGetSessionTokens_sessionRejected
        - MediaController2Test#testConnectToService_libraryService
Change-Id: Ib312aa55403f9ba67644389873c009b7e31c0b00