feat: add searchOperator (minimum_should_match) to bm25 and hybrid arguments

[bevzzz]

This PR adds searchOperator and bm25SearchOperator builder methods to Bm25Argument and HybridArgument builders respectively.

Bm25Argument.builder()
  .query("who's this new operator on the block?")
  .searchOperator(Bm25Argument.SearchOperator.and())
  .build()

HybridArgument.builder()
  .query("but can it OR?")
  .bm25SearchOperator(Bm25Argument.SearchOperator.or(/* minimumMatch: */ 4))
  .build()

Tested via unit tests.

[orca-security-eu]

Orca Security Scan Summary

Status	Check	Issues by priority
Passed	Infrastructure as Code	0   0   0   0	View in Orca
Passed	SAST	0   0   0   0	View in Orca
Passed	Secrets	0   0   0   0	View in Orca
Passed	Vulnerabilities	0   0   0   0	View in Orca