Enable low light clock dream component for new low light behavior.

This change makes the low light dream component available for use when
the low light dream behavior flag is active. Previously, this was made
available for the now defunct low light clock flag.

Fixes: 415848637
Test: manual - verified behavior working on device
Flag: android.os.low_light_dream_behavior
Change-Id: I0401f46b89eb695c2ca06e1dc32f5e8f1758000c