chore: treat datasample queries the same as limited queries

[slim-bean]

What this PR does / why we need it:

datasample queries are use by Grafana for query auto complete as well as "logs sample" on metric queries.

they are generally only helpful if they can return quickly

similar logic here to how we handle "limited" queries (log queries with no label filter)

We shouldn't process these so aggressively in parallel (only do one split by time, at a time) because it's both wasteful and doesn't return a faster result when we only need 10 log lines.

Comparison periods (left with test image, right same time period previous 4 weeks)

Will need to see this run for a few more weeks to really confirm if this impact is consistent (maybe it was less querying during the test week), but generally this looks to be a big benefit

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
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