[flexiglass] Fixes KeyguardKeyEventInteractorTest when flexi is on

Disables two @Test methods that fail when flexi is on. In Flexiglass,
key events captured in bouncer don't go through this code path, instead,
they go directly to media (see
BouncerOverlayContentViewModel#onKeyEvent).

Bug: 283121968
Test: not tested
Flag: EXEMPT test only change
Change-Id: Iaa4ef6577396905acaedcdc1541d2d9df734e654