TV PiP: prevent unnecessary notification updates

Updates have been sent every time the PiP moved (manually or due to
auto-move behavior) since the expansion state is being updated at the
end of each transition. Now checking whether the expand/collapse action
has actually changed.

Bug: 268681026
Test: manual - check that the notification is not being updated by
moving the PiP and checking the TvPipNotificationController logs.
Test: atest TvPipActionProviderTest

Change-Id: I6c3d8697b22acbde8db187897573c70644f98b5c