feat: return human readable error messages from lighthouse celery tasks

[Chan9390]

Context

If user adds an invalid API key, the entire JSON error message is returned.

Celery task output:

Rendering the same error message on frontend looks as follows:

(As highlighted in the PR review - #8925 (comment))

Description

This PR returns just the human readable error message if the message exists in the Exception.

Steps to review

1. Create an OpenAI provider with incorrect API key (sk-xxxxxxx) using the new lighthouse endpoint /api/v1/lighthouse/providers
2. The celery task should return just the error message instead of the entire JSON

Example:

Checklist

• Are there new checks included in this PR? Yes / No
  • If so, do we need to update permissions for the provider? Please review this carefully.
• Review if the code is being covered by tests.
• Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• Review if backport is needed.
• Review if is needed to change the Readme.md
• Ensure new entries are added to CHANGELOG.md, if applicable.

API

• Verify if API specs need to be regenerated.
• Check if version updates are required (e.g., specs, Poetry, etc.).
• Ensure new entries are added to CHANGELOG.md, if applicable.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

⚠️ Changes detected in the following folders without a corresponding update to the CHANGELOG.md:

• api

Please add an entry to the corresponding CHANGELOG.md file to maintain a clear history of changes.

[github-actions]

✅ Conflict Markers Resolved

All conflict markers have been successfully resolved in this pull request.

[Chan9390]

No changelog needed as multi-llm provider support is not rolled out in any release.

[codecov]

Codecov Report

❌ Patch coverage is 73.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.22%. Comparing base (6014951) to head (0302c16).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #9165       +/-   ##
===========================================
+ Coverage   69.31%   94.22%   +24.90%     
===========================================
  Files          84      147       +63     
  Lines        5961    18644    +12683     
===========================================
+ Hits         4132    17567    +13435     
+ Misses       1829     1077      -752     

Flag	Coverage Δ
api	94.22% <73.33%> (?)
prowler-py3.10-iac	?
prowler-py3.10-lib	?
prowler-py3.11-iac	?
prowler-py3.11-lib	?
prowler-py3.12-iac	?
prowler-py3.12-lib	?
prowler-py3.9-iac	?
prowler-py3.9-lib	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
prowler	∅ <ø> (∅)
api	94.22% <73.33%> (∅)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

🔒 Container Security Scan

Image: prowler-api:fea82aa
Last scan: 2025-11-04 15:46:11 UTC

📊 Vulnerability Summary

Severity	Count
🔴 Critical	4
Total	4

3 package(s) affected

⚠️ Action Required

Critical severity vulnerabilities detected. These should be addressed before merging:

• Review the detailed scan results
• Update affected packages to patched versions
• Consider using a different base image if updates are unavailable

---

📋 Resources:

• Download full report (see artifacts)
• View in Security tab
• Scanned with Trivy

[rakan-pro]

LGTM ! note that change log should be adjusted accordingly.