Simplify execute method

ee/app/services/merge_trains/refresh_merge_request_service.rb

@@ -14,7 +14,17 @@ module MergeTrains
       @merge_request = merge_request
 
       validate!
+      pipeline_created = create_or_replace_pipeline
+      merge! if should_merge?
+
+      success(pipeline_created: pipeline_created.present?)
+    rescue ProcessError => e
+      drop(e)
+    end
+
+    private
 
+    def create_or_replace_pipeline
       if should_create_pipeline?
         previous_pipeline = pipeline_for_merge_train
         pipeline_created = create_pipeline!
@@ -22,16 +32,9 @@ module MergeTrains
           previous_pipeline.auto_cancel_running(pipeline_created)
         end
       end
-
-      merge! if should_merge?
-
-      success(pipeline_created: pipeline_created.present?)
-    rescue ProcessError => e
-      drop(e)
+      pipeline_created
     end
 
-    private
-
     def validate!
       unless project.merge_trains_enabled?
         raise ProcessError, 'project disabled merge trains'