Improve organizations groups and projects empty state

What does this MR do and why?

Related to #446243 (closed)

The grouptenant scale team is starting to build out an Organization MVC. For more information about what an "Organization" will be see https://docs.gitlab.com/ee/architecture/blueprints/organization/

This MR improves the search empty state and prevents searching if the term is under 3 characters because the API does not support it.

MR acceptance checklist

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Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Enable the feature flag
   • echo "Feature.enable(:ui_for_organizations)" | gdk rails c
2. Navigate to /-/organizations/default/groups_and_projects
3. Try to search with less than 3 characters
4. Search with a random string that returns no results