release-24.1: workflows: update names of GitHub Action runner groups

[rickystewart]

Backport 1/1 commits from #154698.

/cc @cockroachdb/release

---

These are the new-style names that will make it easier to migrate to Ubuntu 22.04+ when the time comes.

Release justification: Non-production code changes

[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that it falls into one of the following categories (select one):

• Non-production code changes. Includes test-only changes, build system changes, etc.
• Fixes for serious issues. Defined in the policy as correctness, stability, or security issues, data corruption/loss, significant performance regressions, breaking working and widely used functionality, or an inability to detect and debug production issues.
• Other approved changes. These changes must be gated behind a disabled-by-default feature flag unless there is a strong justification not to.

Add a brief release justification to the PR description explaining your selection.

Also, confirm that the change does not break backward compatibility and complies with all aspects of the backport policy.

All backports must be reviewed by the TL and EM for the owning area.

[blathers-crl]

✅ PR #154793 is compliant with backport policy

Confidence: high
Backward compatible: true
Explanation: The pull request is compliant with the backport policy for several reasons. First, it involves a change exclusively to a non-production file (.github/workflows/github-actions-essential-ci.yml) which falls under the Build and CI category of non-production file patterns. Such changes are exempt from the standard backport policy requiring a critical bug justification or feature flag. Second, the PR body correctly includes a 'Release justification' statement indicating that it involves non-production code changes, which is a valid justification for bypassing the standard requirements. Although the PR does not explicitly mention disabling a new feature, it involves non-production workflow updates, making feature flag considerations non-applicable.

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is