AudioFlinger: forward active tracks channel mask to spatializer effect

Partial implementation of track metadata forwarding to effects.
Currently limited to spatializer effect and track channel masks.

Bug: 303920722
Test: atest AudioEffectTest
Test: atest atest android.media.audio.cts.SpatializerTest
Change-Id: Iaaa947f12946d6f87dffb3993612d58f0400e6c5