SOLR-18270 CertAuthPlugin : update the lookup attribute (without parametrization)

[heitzjm]

https://issues.apache.org/jira/browse/SOLR-18270

Description

This PR only update the request attribute used by CertAuthPlugin to match the one filled by Jetty 12 - for SOLR 10. SOLR 9 works fine in the Official Docker Image, as it uses a lower major Jetty version, so it should only be merged in Solr 10 branches (other PR with parametrization that should be suitable for both SOLR 9 and 10 coming).

Solution

This PR only update the request attribute used by CertAuthPlugin to match the one filled by Jetty 12 - for SOLR 10.

Tests

I checked locally by compiling SOLR from source, as well as building Docker Image from source and tested it in a K8S environment.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
  5582 tests completed, 1 failed, 184 skipped
  ERROR: The following test(s) have failed:
  • org.apache.solr.handler.component.AsyncTrackerSemaphoreLeakTest.testSemaphoreLeakOnLBRetry (:solr:core)
    => however, in my opinion, this test does not seem to be relevant for this PR
• I have added tests for my changes.
• I have added documentation for the Reference Guide
• I have added a changelog entry for my change
  unreleased/SOLR-18270-easy-fix-without-parametrization.yml