FIX: Make sure the suspended status is up to date (#8432)

Continuation of #8206

The returned suspend attribute was overwriting a computed property, which made the user admin page go out of sync.

Fixes a computed-property.override deprecation (https://emberjs.com/deprecations/v3.x#toc_computed-property-override)

app/serializers/admin_user_list_serializer.rb

@@ -23,7 +23,6 @@ class AdminUserListSerializer < BasicUserSerializer
              :approved,
              :suspended_at,
              :suspended_till,
-             :suspended,
              :silenced,
              :silenced_till,
              :time_read,
@@ -62,10 +61,6 @@ class AdminUserListSerializer < BasicUserSerializer
     object.silenced_till?
   end
 
-  def suspended
-    object.suspended?
-  end
-
   def include_suspended_at?
     object.suspended?
   end