Update models.py

fix X-rays error

backend/core/models.py

@@ -1290,7 +1290,7 @@ def quality_check(self) -> dict:
         # ---
 
         # --- check on requirement assessments:
-        _requirement_assessments = self.requirementassessment_set.all().order_by(
+        _requirement_assessments = self.requirement_assessments.all().order_by(
             "created_at"
         )
         requirement_assessments = []