Closes ENG-898

Description Of Changes

Retry for pulling custom-fides.css on failures.
Do not disable custom-fides.css polling on failures that are not 404.

Code Changes

• list your code changes here

Steps to Confirm

404 Behavior shuts off polling & Retry does not occur

1. Run the Privacy Center & Fides API.
2. Ensure that there is no api/v1/custom-asset/custom-fides.css uploaded.
3. Load https://localhost:3001/fides.js twice
4. Ensure that api/v1/custom-asset/custom-fides.css is only called once by looking at the server logs.
5. Ensure that Privacy Center does not re-attempt pulling CSS. Use FIDES_PRIVACY_CENTER__LOG_LEVEL=debug to see attempt messages.

Non-404 Behavior will retry and leave CSS polling on

1. Run the Privacy Center
2. Edit src/fidesplus/api/routes/custom_asset.py to return a 500
3. Load https://localhost:3001/fides.js
4. Ensure that api/v1/custom-asset/custom-fides.css is called multiple times via Fides API & Privacy Center logs
5. Load https://localhost:3001/fides.js, observe the same things from step 4 indicating that CSS polling is enabled still

200 behavior is maintained

1. Run the Privacy Center & Fides API
2. Upload custom CSS to api/v1/custom-asset/custom-fides.css
3. Load https://localhost:3001/fides.js twice
4. Observe that api/v1/custom-asset/custom-fides.css is called once

Pre-Merge Checklist

• Issue requirements met
• All CI pipelines succeeded
• CHANGELOG.md updated
  • Add a db-migration This indicates that a change includes a database migration label to the entry if your change includes a DB migration
  • Add a high-risk This issue suggests changes that have a high-probability of breaking existing code label to the entry if your change includes a high-risk change (i.e. potential for performance impact or unexpected regression) that should be flagged
  • Updates unreleased work already in Changelog, no new entry necessary
• Followup issues:
  • Followup issues created
  • No followup issues
• Database migrations:
  • Ensure that your downrev is up to date with the latest revision on main
  • Ensure that your downgrade() migration is correct and works
    • If a downgrade migration is not possible for this change, please call this out in the PR description!
  • No migrations
• Documentation:
  • Documentation complete, PR opened in fidesdocs
  • Documentation issue created in fidesdocs
  • If there are any new client scopes created as part of the pull request, remember to update public-facing documentation that references our scope registry
  • No documentation updates required