Migrate Remove Animations preference to Catalyst backend.

This preference (and its test) has no flagging, but its parent
page 'Color and motion' is flagged for Catalyst migration.

This preference looks identical before and after migration.

Fix: 373451690
Flag: com.android.settings.flags.catalyst_accessibility_color_and_motion
Test: atest RemoveAnimationsPreferenceTest
Test: Enable our flag, and top-level Catalyst flag;
      Toggle the setting in Settings > Accessibility;
      Observe expected changes to animation behavior;
Change-Id: I07dbe45a120780439393d7cfd46a749025b7ab0c