Remove AudioAttributesInternal and media.AudioFlag

There exist equivalent types from the stable package
android.media.audio.common. Switch to these types
and remove duplicates.

Update aidl<->legacy conversions to allow non-vendor
tags within AudioAttributes. Non-vendor tags only get
filtered out on the HAL boundary: cpp<->ndk.

Bug: 281850726
Test: atest audioclient_serialization_tests
Test: atest audio_aidl_ndk_conversion_tests
Test: atest audiorouting_tests
Test: atest audiosystem_tests
Merged-In: If1ff43110c54613c5c29b42a2dc3e5d832708c28
Change-Id: If1ff43110c54613c5c29b42a2dc3e5d832708c28