Refactor all constant imports to module-level access

[WizKnight]

This PR addresses issue #1172 by refactoring constant imports throughout the Hugging Face Hub codebase. It introduces module-level access (from ... import constants) for improved code organization and maintainability.

Key changes:

• Introduced module-level import from . import constants in all relevant files.
• Updated all references to constants to use the new module-level access pattern (e.g., constants.ENDPOINT).

[WizKnight]

Hey @Wauplin, the required changes were done in this PR.

And there is a @patch issue with HUGGINGFACE_CO_URL_TEMPLATE import, while testing. This import is present in huggingface_hub/file_download.py and tests/test_file_download.py

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[Wauplin]

And there is a @patch issue with HUGGINGFACE_CO_URL_TEMPLATE import, while testing. This import is present in huggingface_hub/file_download.py and tests/test_file_download.py

I fixed a last test that was failing locally in 67f9b68. Let's see if CI passes now :)

[Wauplin]

Thanks a lot for this work @WizKnight! Everything looks good to me now and will close #1172 for good :) Thanks again for the contribution 🤗

[WizKnight]

Thankyou, @Wauplin🤗!!! I appreciate your guidance and patience throughout this process. I've learned a lot from you, especially about handling those little mistakes. I'm excited to take on new challenges and would be grateful if you could assign me another task.

[Wauplin]

Hi @WizKnight, glad you took out some learning in the process! Would you be interested in having a look at #2447 for example? It's about adding support for a new endpoint in HfApi. Let me know what you think and if you have any question :)