Use `match` parameter from pytest.raises in tests

tests/test_cache.py

tests/test_element.py

tests/test_elements_worker/test_classifications.py

tests/test_elements_worker/test_dataset.py

tests/test_elements_worker/test_elements.py

tests/test_elements_worker/test_entities.py

tests/test_elements_worker/test_metadata.py

tests/test_elements_worker/test_transcriptions.py

tests/test_elements_worker/test_worker.py

tests/test_image.py

tests/test_merge.py