Deprecate HfApi.list_files_info

[mariosasko]

This PR deprecates the HfApi.list_files_info method, as suggested in #1809 (review),. The usage of this method is still low (based on the GitHub/Hub code search), so this shouldn't cause any problems for the users.

[HuggingFaceDocBuilderDev]

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[mariosasko]

@Wauplin Maybe expect_deprecation (and xfail_on_windows, etc.) should be defined as a pytest marker to support "decorating" test classes, but it's probably better to address this in a separate PR.

[Wauplin]

Thanks for working on that @mariosasko! Left two small comments but overall looks good.

Agree on switching to pytest marks instead of decorators but low priority I think (but I agree the testing suite/utils are quite disparate at the moment).

[Wauplin]

Thanks for making the changes @mariosasko! I'm merging it now :)