Reduce to a single code path through sendBatches regardless of limit

[splitice]

What this PR does / why we need it:

DRY up send batches

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

This should have no great effect on performance. Primarily this makes the code more maintainable.

It's likely not measurable but there is likely a minute cost for the path that had no limit in the past, but this would be absolutely minute.

Checklist

• Documentation added
• Tests updated
• Is this an important fix or new feature? Add an entry in the CHANGELOG.md.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/upgrading/_index.md

[splitice]

This function could be made even simpler if I changed the signature to accept limit as a signed int (where -1 was unlimited, not 0)

Thoughts?

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0.3%
+        distributor	0.3%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
+               loki	0%

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0.3%
+        distributor	0%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
+               loki	0%

[owen-d]

LGTM, nice catch!

I'm fine with using the signed integer, thanks for the cleanup.