Check app-op MEDIA_ROUTING_CONTROL without throwing

The previous check would cause a fatal crash in system_server due to the
app-op check throwing a SecurityException when the app op had been
revoked.

Bug: 330863958
Bug: 326387864
Test: atest ProxyMediaRouter2HostSideTest
Change-Id: I2db1fbeee1852e73feaea8b344c97d2f60cc92f4