chore: [k211] chore: do not shard log queries with empty filter

[grafanabot]

Backport 6569767 from #13568

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What this PR does / why we need it:

Log filter queries are sharded unlike limited queries. But line filters with empty matchers |= "", |~ "" match everything, so we can treat them as limited queries and not shard them to reduce all the parallel work and return early.

This pr updates HasFilter() to return false if the pipeline only contains empty line filter matchers. As a result these queries would now get routed to limited tripperware(which does not shard queries)

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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