Merge branch '19008_ci_dropdown_label_fix' into 'master'

Apply selected value as label

## What does this MR do?

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## What are the relevant issue numbers?

## Screenshots (if relevant)
![dropdown-label](/uploads/db2ea7cb3cc51fbdeea53c304f1bd7a5/dropdown-label.gif)


## Does this MR meet the acceptance criteria?

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

See merge request !4886

app/assets/javascripts/blob/template_selector.js.coffee

@@ -19,6 +19,7 @@ class @TemplateSelector
       data: @data,
       filterable: true,
       selectable: true,
+      toggleLabel: @toggleLabel,
       search:
         fields: ['name']
       clicked: @onClick
@@ -31,6 +32,9 @@ class @TemplateSelector
       @onFilenameUpdate()
     )
 
+  toggleLabel: (item) ->
+    item.name
+
   onFilenameUpdate: ->
     return unless @$input.length
 

spec/features/projects/files/gitignore_dropdown_spec.rb

@@ -24,6 +24,7 @@ feature 'User wants to add a .gitignore file', feature: true do
     end
     wait_for_ajax
 
+    expect(page).to have_css('.gitignore-selector .dropdown-toggle-text', text: 'Rails')
     expect(page).to have_content('/.bundle')
     expect(page).to have_content('# Gemfile.lock, .ruby-version, .ruby-gemset')
   end

spec/features/projects/files/gitlab_ci_yml_dropdown_spec.rb

@@ -24,6 +24,7 @@ feature 'User wants to add a .gitlab-ci.yml file', feature: true do
     end
     wait_for_ajax
 
+    expect(page).to have_css('.gitlab-ci-yml-selector .dropdown-toggle-text', text: 'jekyll')
     expect(page).to have_content('This file is a template, and might need editing before it works on your project')
     expect(page).to have_content('jekyll build -d test')
   end