[App Search] Add small engine breadcrumb utility helper

[cee-chen]

Summary

Adds a super small getEngineBreadcrumbs() utility that populates an engine breadcrumb trail from the currently loaded engine. This DRY's out having to repeatedly pass engineBreadcrumb as a prop to multiple components.

Before:

<SomeView engineBreadcrumb={engineBreadcrumb} />

export const SomeView: React.FC<Props> = ({ engineBreadcrumb }) => (
  <SetPageChrome trail={[...engineBreadcrumb, 'Some parent view', 'Some child view']} />
);

After

import { getEngineBreadcrumbs } from '../engine';

export const SomeView: React.FC = () => (
  <SetPageChrome trail={getEngineBreadcrumbs(['Some parent view', 'Some child view'])} />
);

QA

• All engine breadcrumbs function as before

Checklist

• Unit or functional tests were updated or added to match the most common scenarios

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: b4f7001
• Storybooks Preview
• Documentation Changes

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
enterpriseSearch	2.0MB	2.0MB	-334.0B

History

• 💔 Build #119069 failed 80f934916aefeb5671b359477fb2dbb64e334a50

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[JasonStoltz]

Awesome stuff, this all LGTM.

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	7.x

This backport PR will be merged automatically after passing CI.