Remove dismiss check from security container

An recent change was made to prevent invalid attempts from removing
keyguard. However, it doesn't work in all cases and can prevent valid
unlocks from working. This was causing an empty lockscreen to appear
when SideFPS was used just after locking.

Fixes: 285159911
Test: atest SecurityContainerControllerTest
Test: Use SideFPS device, open an app, hit power but then leave finger
on SideFPS so it attempts to unlock immediately. Must have "Allow
unlock anytime" setting turned on

Change-Id: I547adf2d9865279813d12cb2a6215cf58a7eff0a