ESQL: Merge `Verifier` based function validation into the functions

[nik9000]

Description

In ESQL we mostly validate functions by calling their resolveType methods but for functions that we borrowed from QL in the old, old days we added validation to Verifier so we didn't have to modify the QL classes. That was very hard when we were a branch. But now that we are moving on #106679 we can and should centralize this validation. We should also make sure that we use our normal unit testing for this.

These methods look like they are doing extra, out of band validation:

• [ ] checkOperationsOnUnsignedLong
• [ ] checkBinaryComparison
• [ ] validateBinaryComparison
• [ ] validateUnsignedLongOperator
• [ ] validateUnsignedLongNegation

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[nik9000]

Not fixing this exposes us to fun like #116346. Not a terribly hard bug to fix, but it makes our unit tests very unreliable.