Bug 1535532 - Enable background color animations on the compositor by default on all channels. r=boris

Differential Revision: https://phabricator.services.mozilla.com/D70471

--HG--
extra : moz-landing-system : lando

modules/libpref/init/StaticPrefList.yaml

@@ -3912,7 +3912,7 @@
 
 - name: gfx.omta.background-color
   type: bool
-  value: @IS_NOT_RELEASE_OR_BETA@
+  value: true
   mirror: always
 
 - name: gfx.partialpresent.force