Interactive investigation guides enhancements in 8.9

[joepeeples]

Document the latest enhancements or changes to the interactive investigation guides feature (ongoing work done in 8.6 with https://github.com/elastic/security-docs/issues/2696 and in 8.7 with https://github.com/elastic/security-docs/issues/2955).

Also, the interactive investigation guide feature is set to go GA in the future, and will probably have some licensing/subscription requirements. Exact release TBA.

Related:

• https://github.com/elastic/kibana/issues/153377 From issue description:

  Scope of this feature will now include 3 parts:

  1. hardening of the rendered button, so that we optimistically use fields from old versions with sensible defaults,
  2. ability to delete timeline notes so in the event that invalid markdown is saved as a note, it can be removed by users
  3. wrapping the markdown renderer in a React ErrorBoundary, to prevent any rendering exceptions and also display any relevant parsing errors to the user.

• Epic: https://github.com/elastic/security-team/issues/4824

To Do

• [x] Add info on backwards compatibility, any other new developments
• [x] Update screenshot with new icon in editor
• [x] Remove "technical preview" badge from screenshots
• [x] Relocate page out of Technical preview section

[joepeeples]

Update: This issue originally included the "delete notes in Timeline" change (https://github.com/elastic/kibana/pull/154834), but I broke that out into a separate docs issue since the various features might not all release GA at the same time now: https://github.com/elastic/security-docs/issues/3224

[joepeeples]

Pushed back to 8.9+