Preserve topic repos

[MattIPv4]

Description

Create PreservedTopicPR which will contain all PR IDs that were in the waiting state prior to Hf ending.

Skip the repository topic check for a PR if it is in the preserved list.

Rake task to restore PRs back into the waiting state if they became invalid due to the topic being removed after Hf ended.

Rake task to restore users back into the correct state if their invalid PRs caused them to lose.

Test process

This is absolutely untested, good luck.

Requirements to merge

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code in hard-to-understand areas
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes

[MattIPv4]

After discussion with whole dev team, we have all agreed the user transitions involved are too risky.

[hpoul]

does this mean it's just bad luck if the topic was removed from a repository, or is there a workaround without bothering the project admin to reapply the topic 🤔️

[cy]

does this mean it's just bad luck if the topic was removed from a repository, or is there a workaround without bothering the project admin to reapply the topic 🤔️

Even if the maintainer reapplies the topic, the PRs do not become invalidated, see the discussion in https://github.com/python/typeshed/issues/4631 for an example. Unfortunately, I think all of us sad about this have no workaround since #723 was closed.