audio hal: apply app type gain after device change on VoIP use case

App type specific gain must be reapplied systemaically after a device change
otherwise it is lost.
A typical example is switching from speaker to voice-speaker on a VoIP
stream after volume was applied when the stream started.

Bug: 64972454
Test: place MO duo call and verify intial volume is correct.
Change-Id: I27cabe1690d48d34a0886d1674c7bbf2ec7099e5