[ES|QL] Supports SAMPLE command

[stratoula]

Describe the feature:

With this PR we will enable the SAMPLE command. We will need to support it everywhere:

• AST [ES|QL] support SAMPLE command #221446
• Highlighter Add SAMPLE prismjs-esql#6, Add SAMPLE command highlightjs-esql#7,
• Pretty printer [ES|QL] support SAMPLE command #221446
• Client side validation [ES|QL] support SAMPLE command #221446
• Autocomplete [ES|QL] support SAMPLE command #221446

It seems that the syntax is like:

| SAMPLE probability=decimalValue seed=integerValue?

[elasticmachine]

Pinging @elastic/kibana-esql (Team:ESQL)