[RCA] Add ESQL observation from investigation detail page

[mgiota]

Depends on: https://github.com/elastic/kibana/issues/190320 (feel free to combine these issues if that makes the most sense)

Summary

Allow "add observation" UI component to support ES|QL queries. These queies can produce an observation of type data table, single metric view, or lens chart/visualization.

Acceptance criteria

• "Add observation" component exists, as described in V1 mock up
• In "add observation" component, you can type ES|QL and the results, either a data table, a single metric view, or (with additional help via Lens APIs) a Lens visualization can then be added to the investigation
• NOTE: This version does not need the "Import from" button in the "Add observation" component

Design

The mockup for investigation UI is like this:

However, the left buttons there are specific to KQL only, which we won't implement at first. We should remove those and attempt to bring in the "ES|QL reference" and "Expand query editor" buttons to the right of the above design from logs explorer design, seen below: