Fix stale media metadata

Checking if the metadata object is the same is not enough, we must check if the fields
are also the same, otherwise we can skip events.

It's also necessary to wait for a while before removing the media, otherwise animation
would be janky.

Test: adb shell input keyevent 87
Fixes: 133378688
Change-Id: I7847c8e435f35f4ab596f2aa2cc9296f06d5df26