Only show Pip actions when menu is FULL (i.e. shown)

- The actions container viewgroup should only be visible
when the menu state is FULL
- Update the PipMenuView mMenuState before updating the
action views so that the views reflect the actual new
state of the pip menu.

Bug: 179046413
Test: Enter PiP from Youtube, tap on where the pause
icon would be if the menu was visible, verify it doesn't
pause the video.

Change-Id: I97c55fc12b8eca21a4aa2a94d7890330ca543fc1