Replace ARKINDEX_CORPUS_ID .env variable with an attribute of base_worker corpus_id

tests/test_elements_worker/test_entities.py

@@ -94,7 +94,6 @@ def test_create_entity_wrong_corpus(monkeypatch, mock_elements_worker):
     elt = Element({"id": "12341234-1234-1234-1234-123412341234"})
 
     # Triggering an error on metas param, not giving corpus should work since
-    # ARKINDEX_CORPUS_ID environment variable is set on mock_elements_worker
     with pytest.raises(AssertionError) as e:
         mock_elements_worker.create_entity(
             element=elt,