Drop MctsMediaRouterTestCases

The Cts/Mcts split was carried across when decomposing
MediaBetterTogetherTestCases.  However all of the tests that landed
in router are framework-specific;  the mix of framework/module all
landed in the other MediaSession tests.

Bug: 397770696
Flag: EXEMPT test fix
Test: build, ensure that MctsMediaRouterTestCases is not present
Change-Id: Ib09137d3dcdc1a652ef2925ad4c419e22b810f3e
1 file changed