[ROSP] Add play/pause support for MediaControlChip

This CL adds a playOrPause action to the MediaControlChipModel
which is used to populate the hover icon and click action on
it.
Also, added some tweaks to StatusBarPopupChip's icon to make
the hover icons look better.

Test: Added state change tests in MediaControlChipInteractorTest
Test: Manually confirm music can be play/paused.
See b/385202193 comment#2 for video

Bug: b/385202193
Flag: com.android.systemui.status_bar_popup_chips
Change-Id: I6ca8e0c3efc4def6fb54c81602255280572510a1