Set audio route name when LE audio device is connected

This CL mainly affects how MediaRouter works.
Without this, MediaRouter will not be aware of LE audio routes
even when it's connected so any apps depending on MediaRouter
could break.

This CL makes MediaRouter shows an a2dp bluetooth route, which
may not be correct but we need this for backward compatiblity.

We can remove this when we deprecate MediaRouter.

Tag: #feature
Bug: 211079178
Test: pair LE HS and switch from/to Phone speaker through
the output switcher

Change-Id: I4fe81e000aa13c8d07573780e2abb99eba867f36