MDL-76974 javascript: convert remaining uses of old preferences API.

Implement component preference definition callbacks, update JS code
to use the `core_user/repository` module instead of the now deprecated
API.

lib/javascript-static.js

@@ -160,7 +160,9 @@ M.util.CollapsibleRegion = function(Y, id, userpref, strtooltip) {
         animation.set('reverse', this.div.hasClass('collapsed'));
         // Update the user preference.
         if (this.userpref) {
-            M.util.set_user_preference(this.userpref, !this.div.hasClass('collapsed'));
+            require(['core_user/repository'], function(UserRepository) {
+                UserRepository.setUserPreference(this.userpref, !this.div.hasClass('collapsed'));
+            }.bind(this));
         }
         animation.run();
     }, this, animation);
@@ -577,7 +579,9 @@ M.util.init_block_hider = function(Y, config) {
                     }
                 },
                 updateState : function(e, hide) {
-                    M.util.set_user_preference(this.get('preference'), hide);
+                    require(['core_user/repository'], function(UserRepository) {
+                        UserRepository.setUserPreference(this.get('preference'), hide);
+                    }.bind(this));
                     if (hide) {
                         this.get('block').addClass('hidden');
                         this.get('block').one('.block-hider-show').focus();