Merge branch '24824-dropdown-items-focus' into 'master'

24824 Add focus state to dropdowns

## What does this MR do?
Adds focus state to dropdown items to increase accessibility. 

## Screenshots (if relevant)

![Screen_Shot_2016-12-01_at_2.47.13_PM](/uploads/d0d2c17dde61314c86155268815091f6/Screen_Shot_2016-12-01_at_2.47.13_PM.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #24824

See merge request !7885

app/assets/stylesheets/framework/dropdowns.scss

@@ -188,7 +188,6 @@
     &.is-focused {
       background-color: $dropdown-link-hover-bg;
       text-decoration: none;
-      outline: 0;
     }
 
     &.dropdown-menu-empty-link {

changelogs/unreleased/24824-dropdown-items-focus.yml

+---
+title: Add focus state to dropdown items
+merge_request: 
+author: