Workflow adjustments

[Zeitsperre]

What kind of change does this PR introduce?

• Sets an output condition to prevent subsequent steps from running (without marking the workflow as cancelled/failed).
• Addresses a concurrency issue that occurs when a pull_request_review event cancels a pull_request triggered build.
• Completely removes ubuntu-slim (not compatible with step-security/harden-runner).

Does this PR introduce a breaking change?

Pull request reviews will no longer cancel workflows that have been trigger via pull_request events (synchronize). This should make things a bit easier.

Other information:

Given that this workflow performs a checkout and creates tokens using secrets, we should not be allowing pull_request_target as an allowed trigger.

[github-actions]

Note

It appears that this Pull Request modifies the main.yml workflow.

On inspection, the XCLIM_TESTDATA_BRANCH environment variable is set to the most recent tag (v2025.4.29).

No further action is required.