Update Maximize menu buttons to be 48dp wide

Buttons need to be at least 48x48 to meet a11y guidelines, so updating
snap resize maximize menu buttons to be 48dp wide (and updating the
maximize button to match the new width of the snap resize buttons).

Fix: 397598648
Test: open app in desktop windowing and long press maximize button to
see maximize menu
Flag: EXEMPT bugfix

Change-Id: If45df22bb77519e32d41439dc3380595660897df