Reduce RippleDrawable background opacity when no window focus

Lower the background opacity when the window loses focus
while the view still has focus, in order to prevent user
confusion in a multi-window environment.

Bug: 230355625
Test: manually verified
Change-Id: I59cd7faf35f05a12451f015f8ef2da47077b1bf2
Merged-In: I59cd7faf35f05a12451f015f8ef2da47077b1bf2