[Ingest] Adjust validation UI on data source configuration fields

[jen-huang]

Following the work done in #61180 and #62858, we need to update the validation UI to match design. Here are some additional design notes from @hbharding. Note that the screenshot below shows the form error as a red callout at bottom of page. This should be removed in favor of putting the form error on the bottom bar instead.

View in Figma

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[jen-huang]

@ruflin As these are UI-only adjustments, I'm going to kick this one to beta, hope you don't mind.

@hbharding Would be great to update the mockup for Beta that includes having the general error in bottom bar.