Hide suggestion upvoters in admin to prevent accidental overwrite (T3…

[Stitipragyanbarik]

…75172)

Description

This PR hides the upvoted_users field from the Django admin interface
for Suggestions.

The admin edit form previously exposed a multi-select widget for
upvoters, which could accidentally overwrite existing upvotes when
admins edited unrelated fields such as Phabricator task IDs.

Describe your changes in detail following the commit message guidelines

Rationale

The upvoter list is not intended to be edited manually by administrators.
Exposing it in the admin UI makes it easy to accidentally clear or reduce
upvotes when saving the form.

Hiding this field prevents unintended data loss and improves admin safety.

Phabricator Ticket

https://phabricator.wikimedia.org/T375172

How Has This Been Tested?

• Manually tested via Django admin.
• Edited a suggestion in /admin without modifying upvotes.
• Confirmed that the upvoter list is no longer shown and existing upvotes
  remain unchanged after saving.

Screenshots of your changes (if appropriate):

Types of changes

What types of changes does your code introduce? Add an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Minor change (fix a typo, add a translation tag, add section to README, etc.)

[Stitipragyanbarik]

@Samwalton9 is it solve the issue?

[Samwalton9]

Could you share a screenshot of your changes locally, showing this having the intended effect, please?

[Stitipragyanbarik]

@Samwalton9 can you check now?

[Samwalton9]

That's great, thank you :)

[Stitipragyanbarik]

Thanks for the confirmation!
Please let me know if there’s anything else you’d like me to adjust.

[suecarmol]

Thank you for your PR! A formatting test is failing. Can you run docker-compose exec twlight /venv/bin/black -t py311 /app/TWLight and upload your changes?

[Stitipragyanbarik]

@suecarmol check once

[suecarmol]

Thank you for making these changes!