fix: add a retry middleware to all the stats handlers

[slim-bean]

What this PR does / why we need it:

We use retry middleware for all the subquery downstream requests through the scheduler to the querier, but we did not have any retries on our stats calls which also go through the schedulers downstream to the queriers, this leads to a number of 5xx errors on queries which very likely would have been resolved by a simple retry.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
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[cyriltovena]

LGTM