Add MediaDevice getter for route type

TV needs to differentiate between outputs that are all grouped under
MediaDeviceType.TYPE_USB_C_AUDIO_DEVICE and TYPE_3POINT5_MM_AUDIO_DEVICE
to show some additional settings in the audio output switcher.

Bug: 360215561
Test: builds successfully
Flag: EXEMPT bugfix

Change-Id: I91251bbbfd069d65968b5499d87e6c9fb952f590