Fix NPE when casting

We didn't have any tests that guarantee that the keyguard casting flow
wouldn't be broken by updates on KeyguardStatusView.
Such test was created

Test: atest packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/KeyguardPresentationTest.java
Change-Id: I44f66be770ea2263fbf183bc438d1cedaa6f589a
Fixes: 71696859