fix:When use_spark = True and mlflow_logging = True are set, an error is reported when logging the best model: 'NoneType' object has no attribute 'save' bug Something isn't working

[hexiang-x]

fix:When use_spark = True and mlflow_logging = True are set, an error is reported when logging the best model: 'NoneType' object has no attribute 'save' bug Something isn't working)

Why are these changes needed?

When use_spark = True and mlflow_logging = True are set, an error is reported when logging the best model: 'NoneType' object has no attribute 'save' bug Something isn't working

Related issue number

#1431

Checks

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• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[thinkall]

Thank you very much for the PR, @hexiang-x ! LGTM.

[hexiang-x]

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[hexiang-x]

Thank you very much for the PR, @hexiang-x ! LGTM.

@thinkall Hi, The code is ready to be merged！