[Bug]: Drive action does not comment driving results

[JulianTrommer]

Current Behavior

The last changes to the driving action removed the commenting of the driving results to the PR.
This is due to the fact that the variable github.event_name is not a pull_request because the action is triggered with a workflow_run.

Expected Behavior

The action should check if the pr_id is present in the artifacts (since it is only written if the build action was triggered with a PR) and then post the results to the comments.

How to reproduce the issue

See the last PRs and actions.