Use route name for output switcher chip

The media router 2 library can include device group names when casting
to a group. So if the route name is available, use that instead of the
LMM device name.

If the route name is not available, we fall back to the LMM device name.
The output switcher will still show as disabled (chip is not clickable and
reads "Other device") if either the device or route is null.

Test: manual, using sample app
Test: atest MediaDeviceManagerTest MediaControlPanelTest
Fixes: 196923854
Fixes: 199951690
Change-Id: I07afbab3f62e6bc7855e0d5623c577231eb3500b