audio policy: improve capture policy for clients with same UID

Modify concurrent capture logic to allow different policies
applied to record clients sharing the same UID.
Previously, because the control granularity was the UID, we had to
enforce the same decision for all clients with the same UID.
Now that audio flinger and audio policy manager APIs to silence capture
are per port ID, we can apply a different policy for each record instance.

Bug: 139370731
Test: AudioRecordTest#testRecordNoDataForIdleUids

Change-Id: I533b74602fa465fd5df7f848eca48dfd49b424c8