[EuiSelectable]: onSearch should also return visibleOptions

[eeston]

Fixes #5165

EuiSelectable has no way (that I can see) of returning the visibleOptions list per character typed (with searchable: true). I've added this functionality to onSearch so that it now returns visibleOptions as the second parameter, as opposed to just the searchValue.

Checklist

- [ ] Check against all themes for compatibility in both light and dark modes
- [ ] Checked in mobile
- [ ] Checked in Chrome, Safari, Edge, and Firefox

• Props have proper autodocs and playground toggles
• Added documentation
  - [ ] Checked Code Sandbox works for any docs examples
  - [ ] Added or updated jest tests
  - [ ] Checked for breaking changes and labeled appropriately
  - [ ] Checked for accessibility including keyboard-only and screenreader modes
• A changelog entry exists and is marked appropriately

[kibanamachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[cla-checker-service]

💚 CLA has been signed

[cchaos]

🙌 Welcome and thanks for the PR @eeston!

Would you please sign the CLA linked below (if you haven't already). Be sure to use the same email address linked to your Github account.

Also, if you can, please write a bit more in the description of the PR about how you went about fixing the linked issue, that would help us a lot in review.

I've also unchecked a PR checklist item about prop autodocs, since I think we should add a prop comment explaining what onSearch returns back to help others down the road.

But, I'll get our CI (Jenkins) started for you which will run our tests and get a preview built.

Jenkins, test this

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_5178/

[eeston]

Hi @cchaos !

Thanks for the initial feedback. I've signed the CLA & I think I've covered everything I need to do in terms of prop autodocs. If there's anything else, please let me know.

In terms of PR information, there's some information here #5165. It has the intial issue I raised and a quick chat with @thompsongl about how to address it.

Quick summary: EuiSelectable has no way (that I can see) of returning the visibleOptions list per character typed (with searchable: true). I've added this functionality to onSearch so that it now returns visibleOptions as the second parameter, as opposed to just the searchValue.

[cchaos]

Thanks for the context. Sometimes it's just helpful to reiterate in the PR itself as to the final approach taken.

Jenkins, test this

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_5178/

[thompsongl]

jenkins test this

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_5178/

[thompsongl]

jenkins test this

[thompsongl]

LGTM; Thanks, @eeston!

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_5178/

[eeston]

Thanks @thompsongl