audio: Clarify profiles management for external devices

Clarify what should happen to mix port profiles after
connection of an external device. Add a test to verify
this behavior.

Also, add an XML file for the test runner for
VtsHalAudioCoreTargetTest.

Bug: 273252382
Test: atest VtsHalAudioCoreTargetTest
Change-Id: I3381dd29c5922bf31fa3a8ae6fa273597e8333a1
Merged-In: I3381dd29c5922bf31fa3a8ae6fa273597e8333a1