chore(ci): Show tested modules in GitHub Actions step summary

[gnodet]

Summary

When reviewing CI results for a PR, it's not immediately clear which modules were tested. You have to download the log artifact and search for the reactor list.

This adds the module list directly to the GitHub Actions step summary, visible in the PR checks UI:

• Changed modules: the directly affected modules (from the PR diff)
• All tested modules (collapsible): the full reactor list including downstream dependents

The failure table (for failed tests) is preserved and appended after the module list.

Example output

Changed modules

• components/camel-jms
• test-infra/camel-test-infra-artemis

All tested modules (42)

• Camel :: ActiveMQ 5.x
• Camel :: ActiveMQ 6.x
• Camel :: AMQP
• Camel :: JMS
• ...

[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.