Fixes the hover color of app handle menu buttons

Previously, app handle menu buttons used RippleDrawable for their
background. This prevented setting a specific hover background color, as
RippleDrawable automatically uses a 20% alpha version of the ripple
color for hover effects.

This change replaces RippleDrawable with ShapeDrawable, which allows the
desired hover background color to be set.

Video: http://recall/-/dvR0xNyCWFr2PAfPfPhsQ6/ey9AVamOsC6vezHYo5Y560
Bug: 400529749
Test: None
Flag: com.android.window.flags.enable_desktop_windowing_mode
Change-Id: I092fa5a76a5998f8224ffeb264396152770a4e4e