Hook up compose for keyguard.

Adds some fixes for compose in keyguard.

Hooks up keyguard written in compose to replace ConstraintLayout. It is
behind a DEVELOPMENT flag

Fixes:
Added burn in parameters to small clock so that it translates properly
in AOD. Burn in alpha is stuck between 0f and 1f. Ensures that alpha is
1f when it finishes.

Add bottom padding for smartspace so NSSL has some space below
smartspace.

Bug: 301968149
Test: Ensure all views exist in KeyguardRootView. View lockscreen with
flag on.
Flag: ACONFIG com.android.systemui.enable_keyguard_compose DEVELOPMENT

Change-Id: I39991a96998ec8ae0cd534c4fc83d9701cd04241