Updated test_tdamm_tags to use the value from post_generation decorator

Author: dhanur-sharma

sde_collections/tests/test_tdamm_tags.py

@@ -22,7 +22,7 @@ def test_manual_and_ml_field_behavior(self):
         # Setting tdamm_tag affects only manual field
         url.tdamm_tag = ["MMA_M_EM", "MMA_M_G"]
         assert url.tdamm_tag_manual == ["MMA_M_EM", "MMA_M_G"]
-        assert url.tdamm_tag_ml is None
+        assert url.tdamm_tag_ml == []
 
         # ML field must be set explicitly
         url.tdamm_tag_ml = ["MMA_M_N"]