audioflinger: fix mmap rerouting on track invalidation

When mmap tracks are invalidated by audio policy manager to request
a reconnection of the client to another output, do not send an onTearDown()
callback to AAudioService but an onRoutingChanged() callback to force
the stream disconnection.

Bug: 246803857
Test: repro steps in bug
Change-Id: I92b759a90d13c36052c9b39de17731b0214bb673
Merged-In: I92b759a90d13c36052c9b39de17731b0214bb673