cleanup(net): Deleted unused NeverAttemptedAlternate peer state

[teor2345]

Motivation

We want to remove an unused peer state.

This is a cleanup from #7824. I think we can close that tracking issue after it merges, as soon as we decide what to do about the more complicated cleanups.

PR Author Checklist

Check before marking the PR as ready for review:

• Will the PR name make sense to users?
• Does the PR have a priority label?
• Have you added or updated tests?
• Is the documentation up to date?

If a checkbox isn't relevant to the PR, mark it as done.

Solution

• Remove the NeverAttemptedAlternate peer state and everything that depends on it
• Add a Debug impl for CandidateSet

Testing

This also involves updating tests, which currently give good coverage.

Review

This is a low priority cleanup. I don't want to merge it into PR #7977, just in case we need to revert it.

Reviewer Checklist

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• Does the PR scope match the ticket?
• Are there enough tests to make sure it works? Do the tests cover the PR motivation?
• Are all the PR blockers dealt with?
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And check the PR Author checklist is complete.

[teor2345]

This removes internal unused code, so it doesn't need extra reviews.

[teor2345]

@Mergifyio refresh

[mergify]

refresh

✅ Pull request refreshed

The base branch was changed.