Clean up security view modes onDestroy

With SIM support on large screens, it is possible to enter and
leave the USER_SWITCHER mode in favor of the SIM screens. Clean
up prior constraints and remove views to ensure they do conflict
as modes are changed.

Fixes: 365732215
Test: atest KeyguardSecurityContainerTest
Flag: EXEMPT bugfix
Change-Id: I608d5fb723e84a430595f0525bc1be7c3d932585