stagefright: update MediaCodec clients to handle all callbacks

Update callback handlers for MediaCodec clients to handle newer
callbacks, such as CB_METRICS_FLUSHED. This was only a breaking issue
for NuPlayer as it crashed on unhandled callbacks, but added handlers
to all other MediaCodec users for completeness.

Bug: 391519300
Change-Id: Ifeed3c9bee926294e14425e050ceb29dd8ae7d8b
Flags: EXEMPT bugfix
Test: local CTS, need to find a place for it