Expand/collapse JSON in discover

[timroes]

During the switch to React we switched over to use the EuiCodeBlock component, which in contrast to the previous Angular version, does not allow expanding and collapsing of parts of the JSON, as long as you view the JSON.

It seems (see linked issue below) that this request comes up. I think we should consider, maybe using a different implementation here maybe.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[felix-lessoer]

Its not only in the JSON view but maybe also a good idea in the field view in general. As ECS has a lot of multi level fields it would also improve the UX for looking to those fields.

[kertal]

Linking #69614, also line numbers are missed

[kertal]

I can see 3 ways how we could proceed in this case:

1. Improve EuiCodeBlock with line numbers and expanding/collapsing
2. Step back to EuiCodeEditor (Using Ace under the hood) https://elastic.github.io/eui/#/forms/code-editor
3. Use Monaco which is now available in Kibana to create something new

[timroes]

Just wanted to leave this note for prosperity: The current EUI recommendation are saying we should use monaco for it, which is available in Kibana.

[timroes]

Closed via #90781