Prefer querying ingester zones with the least number of non-ACTIVE ingesters

[charleskorn]

What this PR does

This PR builds on #6726 to try to mitigate the issue described near the end of the PR description:

Note that the downside of this change is that queriers will attempt to query ingesters that are possibly still starting up, and may not be ready to receive requests. In this case, hedging will cause the querier to try other ingesters, if available, after at most 2s, or sooner if the connection to the ingester fails before hedging is triggered, and one of the following will happen:

• If ingesters in other zones are healthy, then the impact is simply increased latency. An improvement for this would be to prioritize querying zones where all ingesters are ACTIVE, but I will add this in a follow up PR.
• ...

This PR mitigates this issue by prioritising querying ingester zones that have the least number of non-ACTIVE ingesters. This means a querier is less likely to choose a zone with a PENDING ingester and so is less likely to query an ingester that is still in the process of starting up, fail and need to initiate requests to a third zone.

This PR requires grafana/dskit#440 to be merged first.

Which issue(s) this PR fixes or relates to

Related: #6726
Related: grafana/dskit#440

Checklist

• Tests updated.
• [n/a] Documentation added.
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• about-versioning.md updated with experimental features.