[ES|QL] RERANK Command - Inference Id should be optiona

[afoucret]

Acceptance creiteria:

• The inference id is optional and default to the default reranker (.rerank-v1-elasticsearch)
• Using the default reranker must trigger its download (and automatic deployment)

[elasticsearchmachine]

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

[afoucret]

PR is here: #128685