fix: update ForeignKey on_delete behavior for ApplicationKnowledgeMapping

Author: liuruibin

apps/knowledge/models/knowledge.py

@@ -203,8 +203,8 @@ class Meta:
 
 class ApplicationKnowledgeMapping(AppModelMixin):
     id = models.UUIDField(primary_key=True, max_length=128, default=uuid.uuid7, editable=False, verbose_name="主键id")
-    # application = models.ForeignKey(Application, on_delete=models.CASCADE)
-    knowledge = models.ForeignKey(Knowledge, on_delete=models.CASCADE)
+    # application = models.ForeignKey(Application, on_delete=models.DO_NOTHING)
+    knowledge = models.ForeignKey(Knowledge, on_delete=models.DO_NOTHING)
 
     class Meta:
         db_table = "application_knowledge_mapping"