CAMEL-22527: Fix flaky JettyFailoverRoundRobinTest

[gnodet]

Summary

• Fix flaky JettyFailoverRoundRobinTest that intermittently fails with BindException on CI
• Root cause: static AvailablePortFinder.getNextAvailable() doesn't release ports, causing conflicts in parallel test runs
• Fix: use @RegisterExtension AvailablePortFinder.Port with proper lifecycle management and @AfterEach cleanup
• Move URL construction into createRouteBuilder() where port values are available

Test plan

• Verified with multiple local runs
• mvn test -B -pl components/camel-jetty -Dtest=JettyFailoverRoundRobinTest

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com

[github-actions]

🌟 Thank you for your contribution to the Apache Camel project! 🌟
🤖 CI automation will test this PR automatically.

🐫 Apache Camel Committers, please review the following items:

• First-time contributors require MANUAL approval for the GitHub Actions to run
• You can use the command /component-test (camel-)component-name1 (camel-)component-name2.. to request a test from the test bot although they are normally detected and executed by CI.
• You can label PRs using build-all, build-dependents, skip-tests and test-dependents to fine-tune the checks executed by this PR.
• Build and test logs are available in the summary page. Only Apache Camel committers have access to the summary.

⚠️ Be careful when sharing logs. Review their contents before sharing them publicly.

[apupier]

/component-test jetty

[github-actions]

✅ /component-test jetty tests passed successfully.

⚠️ Some integration tests are disabled on GitHub Actions (@DisabledIfSystemProperty(named = "ci.env.name")) and require manual verification:

• components/camel-jetty: 3 test(s) disabled on GitHub Actions

[github-actions]

🧪 CI tested the following changed modules:

• components/camel-jetty