* ES|QL SAMPLE aggregation function (#127629)

* ES|QL SAMPLE aggregation function

* [CI] Auto commit changes from spotless

* ThreadLocalRandom -> SplittableRandom

* Update docs/changelog/127629.yaml

* fix yaml test

* Add SampleTests

* docs + example

* polish code

* mark generated imports

* comment with algorith description

* use Randomness.get()

* close properly

* type checks

* reuse hash

* regen some files

* [CI] Auto commit changes from spotless

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Co-authored-by: elasticsearchmachine <infra-root+elasticsearchmachine@elastic.co>

* Fix + unmute SampleTests (#127959)

* Fix memory tracking of ES|QL sample agg (#128467)

* Fix memory tracking of ES|QL sample agg

* [CI] Auto commit changes from spotless

* polish code

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Co-authored-by: elasticsearchmachine <infra-root+elasticsearchmachine@elastic.co>

* ESQL: Unclean generated imports (#127723)

This removes a ton of the tricky juggling we do for generated java files
to keep the imports in order. Instead, we just live with them being out
of order a little. It's not great, but it's so so so much easier than
the terrible juggling we had been doing.

* ESQL: Disable format checks on generated imports (#127648)

This builds the infrastructure to disable spotless and some checkstyle
rules on generated imports. This works around the most frustrating part
of ESQL's string template generated files - the imports. It allows
unused and out of order imports. This can let us remove a lot of
cumbersome, tricky, and fairly useless `$if$` blocks from the templates.

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Co-authored-by: elasticsearchmachine <infra-root+elasticsearchmachine@elastic.co>
Co-authored-by: Nik Everett <nik9000@gmail.com>