audio: Remove android.hardware.audio.core.AudioMode type

I missed that there is already android.media.audio.common.AudioMode.
However, due to use by the framework, it contains more values
(all of them are SYS_RESERVED), thus the implementation and VTS
have to be updated as well.

Bug: 205884982
Test: atest VtsHalAudioCoreTargetTest
Change-Id: If260413b1f774a69514de978792d5ad2eb46481a
Merged-In: If260413b1f774a69514de978792d5ad2eb46481a