Fix ripple effect for floating toolbar menu items

A corner radius was set for the floating toolbar in
Ifcf4cff1f38fd18b7dbb4c1802390e3beb92cd3c. This produced a bug, where
the ripple effect set on the floating toolbar menu items was expanding
outside the corners when these were pressed.

This CL sets the menu items container to clip to outline, such that the
ripple effect of the menu items will be clipped.

Bug: 77547543
Test: manual testing
Change-Id: Ib43a6c719aab1403273f47e559433c9856b4f8b4