Remove MovableElement for small clock.

Small clock does not animate when in a movable element. I'm not entirely
sure why, but there doesn't seem to be any issue if the small clock just
uses the elemen modifier key.

Fixes: 332550069
Test: Switch between small clock and large clock.
Flag: ACONFIG com.android.systemui.compose_lockscreen DEVELOPMENT
Change-Id: Iaa2e6462bef20ea88684f57940936b69ac649e04