CI: allow passing HF_TOKEN to python-test workflow

[CodeVishal-17]

Pull Request

Description

Adds an optional hf_token input to the reusable python-test workflow and
exposes it as HF_TOKEN during pytest execution.

This allows CI jobs to authenticate with Hugging Face when needed, while
remaining fully optional and backwards compatible.

Fixes #86

How Has This Been Tested?

This change was validated by reviewing the workflow configuration and ensuring
it remains backwards compatible.
The change is backwards compatible and does not alter CI behavior when
hf_token is not provided.

• Yes

If your changes affect data processing, have you plotted any changes? i.e. have you done a quick sanity check?

• Yes

Checklist:

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have checked my code and corrected any misspellings

[CodeVishal-17]

Hi, just checking if any changes are needed from my side. Happy to update.