[ML] Client-Side Job Validation v6.3.x

[walterra]

This is a follow up to #18349 (Client side job validation for v6.3), where the general validation framework and initial checks have been implemented. This issue tracks the planned updates for job validation in v6.3.x.

v6.3.x

Bugs

• elasticsearch error when aggregating _source [ML] Job Validation - elasticsearch error when aggregating _source #18516
• model memory format check is too generous and is sometimes skipped [ML] Job Validation - model memory format check is too generous and is sometimes skipped #18764

[elasticmachine]

Pinging @elastic/ml-ui

[walterra]

Closing, moved to general job validation meta issue #18368