Merge branch 'fix-todo-mobile-view' into 'master'

Fix todos page mobile viewport layout

## What does this MR do?
Fixes the todos page mobile viewport layout

## Are there points in the code the reviewer needs to double check?
Shouldn't be any 👍 

## Why was this MR needed?
Improve GitLab usability on mobile devices

## Screenshots (if relevant)
Before:
![Simulator_Screen_Shot_Sep_13__2016__11.30.19_AM](/uploads/7053a1bb1fca6238c5f86d671bf96ff0/Simulator_Screen_Shot_Sep_13__2016__11.30.19_AM.png)

After:
![Simulator_Screen_Shot_Sep_13__2016__11.30.04_AM](/uploads/a30921c1a1118655b547977872e8e1c7/Simulator_Screen_Shot_Sep_13__2016__11.30.04_AM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [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)

## What are the relevant issue numbers?
Closes #22097

See merge request !6325

CHANGELOG

@@ -20,6 +20,7 @@ v 8.13.0 (unreleased)
   - Allow the Koding integration to be configured through the API
   - Added soft wrap button to repository file/blob editor
   - Add word-wrap to issue title on issue and milestone boards (ClemMakesApps)
+  - Fix todos page mobile viewport layout (ClemMakesApps)
   - Fix robots.txt disallowing access to groups starting with "s" (Matt Harrison)
   - Close open merge request without source project (Katarzyna Kobierska Ula Budziszewska)
   - Add configurable email subject suffix (Fu Xu)

app/assets/stylesheets/pages/todos.scss

@@ -51,6 +51,7 @@
     -webkit-flex-direction: column;
     flex-direction: column;
     margin-left: 10px;
+    min-width: 55px;
   }
 
   .todo-item {
@@ -120,6 +121,14 @@
   }
 }
 
+@media (max-width: $screen-sm-max) {
+  .todos-filters {
+    .dropdown-menu-toggle {
+      width: 135px;
+    }
+  }
+}
+
 @media (max-width: $screen-xs-max) {
   .todo {
     .avatar {
@@ -141,4 +150,14 @@
       padding-left: 10px;
     }
   }
+
+  .todos-filters {
+    .row-content-block {
+      padding-bottom: 50px;
+    }
+
+    .dropdown-menu-toggle {
+      width: 100%;
+    }
+  }
 }