Remove unused code for `no_matching_runner` failure reason

What does this MR do?

Reverts the changes introduced for https://gitlab.com/gitlab-org/gitlab/-/issues/323486 that are not needed anymore. We used to drop the jobs that didn't match any active runner when the pipeline is created, but it turns out that is common for the users to spin up runners from a pipeline to handle jobs in later stages. We've removed the code that was dropping the jobs with no_matching_runner failure reason in !63542 (merged) and now we're doing the final clean-up.

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