Upgrade mimir-prometheus

[charleskorn]

What this PR does

This PR upgrades mimir-prometheus to include the changes from grafana/mimir-prometheus#833.

As mentioned in that PR:

This PR only includes a single upstream PR: prometheus/prometheus#15851.

The main potentially problematic change is the new default value of model.NameValidationScheme, which has switched to UTF8Validation. I believe this change is safe to bring into Mimir, as we already set model.NameValidationScheme to LegacyValidation in multiple places (1, 2, 3) that should cover all components that need to validate label names.

Full diff of prometheus/common changes: prometheus/common@v0.61.0...v0.62.0

Full diff of prometheus/client_golang changes: prometheus/client_golang@v1.20.5...v1.21.0-rc.0 (changelog)

There are no changes between v1.21.0-rc.0 and v1.21.0 of prometheus/client_golang.

Which issue(s) this PR fixes or relates to

(none)

Checklist

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