audio: Fix IStreamIn.getActiveMicrophones test

Since "active" means "used by the stream for acquiring data,"
it was unreasonable to expect the list of active microphones
to be non-empty prior to actually starting data acquisition.
This change adds running of 'burst' commands before calling
'getActiveMicrophones'.

To reuse existing code some refactorings have been made.
Added 'AudioInputFlags::HOTWORD_TAP' to the list of port
config flags for which I/O testing is not performed.

Bug: 328010709
Bug: 328362233
Test: atest VtsHalAudioCoreTargetTest
Change-Id: I876c0b6d7365e104ec9ed8cf5033a83f822006b6