[Enterprise Search][bug/tech debt] Fix route navigation

[cee-chen]

Summary

Thanks to some help from Josh Dover, Nathan Smith, and Pierre Gayvallet's original PR comment, I realized that our entire app was unmounting and remounting (also causing our Kea/Redux state to unmount & remount) on every in-app navigation when it should not have been.

This was happening because we were not using correctly Kibana's history navigation but instead directly accessing history.push().

This PR fixes all instances of history.push() to navigateToUrl() (and refactors our breadcrumbs helper to use hooks in order to simplify not passing around context). I recommend following along by commit.

QA

• With enterpriseSearch.host set:
  • Go to App Search and confirm it redirects you to the Engines Overview (URL: /engines)
  • Click on "App Search" in the Kibana breadcrumbs and confirms it redirects you again back to the Engines Overview and does not show a blank page
  • Manually go to http://localhost:5601/app/enterprise_search/app_search/setup_guide, click on App Search in the Kibana breadcrumbs, and confirm it redirects you to Engines Overview and does not break/show a blank page
  • Go to Workplace Search and confirm their breadcrumbs still works as before
• With enterpriseSearch.host unset/commented out, from Kibana home:
  • Go to App Search and confirm it redirects you to the Setup Guide
  • Click on "App Search" in the Kibana breadcrumbs and confirms it redirects you again back to the Setup Guide and does not show a blank page
  • Go to Workplace Search and confirm it redirects you to the Setup Guide
  • Click on "Workplace Search" in the Kibana breadcrumbs and confirms it redirects you again back to the Setup Guide and does not show a blank page

Checklist

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

[cee-chen]

To test that unmounting and mounting is not still happening, you can go here:

kibana/x-pack/plugins/enterprise_search/public/applications/index.tsx

Line 69 in ba1ad51

return () => ReactDOM.unmountComponentAtNode(params.element);

and add a console.log('hello world') and check how many times 'hello world' logs between breadcrumb navigations.

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 947844e

Build metrics

async chunks size

id	value	diff	baseline
enterpriseSearch	359.3KB	+218.0B	359.1KB

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

[scottybollinger]

Looks great! Pulled it down locally and it works great. 🎉