chore: remove deprectated (and unsupported) workflow runner types

[back-of-house-staging]

What

For every github workflow in this repository, change workflow runners from the deprecated multi-label syntax to the new single-label syntax.

┌────────────────┐       ┌─────────────────┐  
│ runs on: [...] │  ->   │  runs on: ...   │
└────────────────┘       └─────────────────┘

Why

Github Workflow Syntax Deprecation

The multi-label syntax for selecting Github Action Runners is no longer supported, and will be replaced by a single label selector.
Support for multi-label selectors will be fully removed by June 14th, 2024 at 5 PM EST. If your workflows are not updated by this time, they will not be picked up by SpotOn's self-hosted runners and will hang indefinitely.

This automated PR removes the deprecated runner selector syntax from GitHub Actions workflows, and attempts to replace them with the latest syntax. If the syntax cannot be automatically replaced, the runner will be removed and a comment will be added to the PR with the details. We cannot automatically patch runner selectors that have been templated. If a runs-on line is detected in your workflow, we will leave a comment on that line.

Please review this PR, make any manual changes required by cloning the branch to your local machine, and then merge the PR. Migration to the new selector style should not affect your workflow behavior in any way, but please verify before merging. If you have any questions or concerns, please reach out to the #devops channel in slack.

[MaxymVlasov]

GH workers are free for public repos, so I don't see the reason for switching to private workers which cost us money (as we pay for resources where such workers run)

GitHub Actions usage is free for standard GitHub-hosted runners in public repositories,
https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions