ci: Replace local RL scanner with reusable action

[kailash-b]

✏️ Changes

Migrates the ReversingLabs (RL) malware scan from this repo's local composite action to the shared, maintained reusable action in auth0/devsecops-tooling, so all Auth0 SDKs use one common scanner.

• .github/workflows/rl-secure.yml: The "Run RL Scanner" step now uses auth0/devsecops-tooling/.github/actions/rl-scan@main instead of the local ./.github/actions/rl-scanner. Two new required secrets were added to the workflow_call definition: SIGNAL_HANDLER_DOMAIN and PRODSEC_PYTHON_TOOLS_REPO.
• .github/workflows/release.yml: Wired the two new secrets (SIGNAL_HANDLER_DOMAIN, PRODSEC_PYTHON_TOOLS_REPO) into all three rl-scanner-* job calls.
• .github/actions/rl-scanner/action.yml: Deleted - the shared reusable action fully replaces it, and there are no remaining references in the repo.

🔗 References

🎯 Testing

• This change adds unit test coverage. N/A (CI workflow change)

• This change adds integration test coverage. N/A (CI workflow change)

• This change has been tested on the latest version of the platform/language or why not. N/A (CI workflow change)

✅ Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors

• All commits are signed.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.32%. Comparing base (1c1461d) to head (b00d8d7).

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #68      +/-   ##
==========================================
- Coverage   92.53%   92.32%   -0.21%     
==========================================
  Files          29       29              
  Lines        1433     1433              
  Branches      164      164              
==========================================
- Hits         1326     1323       -3     
- Misses         76       78       +2     
- Partials       31       32       +1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[kishore7snehil]

There is one caller here, rl-secure.yml could be inlined into release.yml and removed.

[kishore7snehil]

LGTM!