Do not return partial data if 422 or half of fleet is down

[justinjung04]

What this PR does:

This PR enhances partial data feature used in ingesters and rulers with the followings:

1. If queryable return 422, return 422 instead of partial data
2. If at least half of ingesters are down, return 5xx instead of partial data
3. Enhance partial data log with user and request info

Which issue(s) this PR fixes:
n/a

Checklist

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

[justinjung04]

I thought these are minor improvements that don't need to be in the changelog, but please let me know if you'd like me to add.

[justinjung04]

The test-no-race is failing due to issue unrelated to this PR. Here's the fix: #6768

[yeya24]

Thanks!