Extend dashboard YAML definion validation to exhaustive list of errors

What does this MR do?

It re adds changes from !38925 (merged) because original MR was reverted due to introduced regression #238606 (closed) This time changes are hidden behind feature flag (metrics_dashboard_exhaustive_validations), so make sure that behavior observed on review apps and local development instance is consistent with the one from production environment. Documentation and changelog will be added when feature flag will be cleared.

See #241697 for the roll out issue.


Does this MR meet the acceptance criteria?


Reports #219398 (closed)

Edited by Mikołaj Wawrzyniak