Transition from type::* labels to GitHub Issue Types

[kenodegard]

Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

GitHub Issue Types are in beta.

They are already supported in issue forms so with minor effort this can be adopted by all projects for their issue management.

The main difference with the new types is they're mutually exclusive (only one type can be assigned to an issue) while we can assign any number of type::* labels to an issue. Usually this is not a problem and the original intention was for type::* to be mutually exclusive.

The second "problem" with switching to GitHub Issue Types is how this is an issue only field. We'd no longer be able to label a PR with a type. Honestly this isn't terrible since most PRs tend to have an associated issue with details.

Why is this needed?

Our test::* labels and GitHub Issue Types are redundant features. Might as well remove our custom implementation in favor of GitHub's solution.

What should happen?

Replace type::* with the new type field.

Additional Context

No response