Move abilities by subject class to a dedicated method (EE)

This will avoid lame conflicts when merging CE to EE
Signed-off-by: Rémy Coutable <remy@rymai.me>

app/models/ability.rb

@@ -6,7 +6,14 @@ class Ability
       return [] unless user.is_a?(User)
       return [] if user.blocked?
 
-      abilities =
+      abilities = abilities_by_subject_class(user: user, subject: subject)
+
+      abilities -= license_blocked_abilities if License.block_changes?
+
+      abilities
+    end
+
+    def abilities_by_subject_class(user:, subject:)
       case subject
       when CommitStatus then commit_status_abilities(user, subject)
       when Project then project_abilities(user, subject)
@@ -24,10 +31,6 @@ class Ability
       when Ci::Runner then runner_abilities(user, subject)
       else []
       end.concat(global_abilities(user))
-
-      abilities -= license_blocked_abilities if License.block_changes?
-
-      abilities
     end
 
     def license_blocked_abilities