Fix chunk_constraint_drop_constraint (#7181)

Author: pierreforstmann

.unreleased/pr_8496

@@ -0,0 +1,2 @@
+Implements: #8496 Fix dropping chunks with foreign keys
+Thanks: @pierreforstmann for fixing a bug when dropping chunks with foreign keys

src/chunk_constraint.c

@@ -954,7 +954,8 @@ chunk_constraint_drop_constraint(TupleInfo *ti)
 		};
 
 		if (OidIsValid(constrobj.objectId))
-			performDeletion(&constrobj, DROP_RESTRICT, 0);
+			/* must use DROP_CASCADE if regular table references a hypertable */
+			performDeletion(&constrobj, DROP_CASCADE, 0);
 	}
 }