Fix pre-commit isort failure on tests/checkpointing/*.py (#5427)

* Remove tests.checkpointing from skipped module in pyproject.toml

* Fix pre-commit isort failure on tests/checkpointing/*.py

pyproject.toml

@@ -39,7 +39,6 @@ skip_glob = [
     "tests/backends/*",
     "tests/base/*",
     "tests/callbacks/*",
-    "tests/checkpointing/*",
     "tests/core/*",
     "tests/loggers/*",
     "tests/metrics/*",

tests/checkpointing/test_trainer_checkpoint.py

@@ -11,8 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from copy import deepcopy
 import os
+from copy import deepcopy
 
 import torch