CI: Spinup unique cirun runners for each job

[aktech]

Sometimes it happens, when a runner is created for a job, it gets consumed by a job queued earlier, causing confusion sometimes. This PR makes sure, the runner is only consumed by the job it was created by. It's cirun's new feature, read more here: https://docs.cirun.io/reference/unique-runner-labels

Reference Issues or PRs

What does this implement/fix?

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features not to work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Testing

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• Did you add new tests?

Any other comments?

[viniciusdc]

LGTM