🎨 DRY accessing the submission steps

This is available on the model too, so we can build on
top of that.

src/openforms/submissions/rendering/renderer.py

@@ -52,8 +52,7 @@ def steps(self):
         """
         Return the submission steps in the correct order.
         """
-        execution_state = self.submission.load_execution_state()
-        return execution_state.submission_steps
+        return self.submission.steps
 
     @property
     def has_children(self) -> bool: