Ensure we draw through the box-shadow
Ensure we draw through the box-shadow

This is destructive but ensures our tail itself can be properly themed
and not subject to "leaking" box-shadows coming through from behind.

Signed-off-by: Ikey Doherty <d8d992cf0016e35c2a8339d5e7d44bebd12a2d77@solus-project.com>

ikeydoherty/ui-tests,ikeydoherty/ui-tests