Merge branch 'issue_14353' into 'master'

Ignore toggling the sidebar for resolutions over 1200px width

Closes #14353 
![sidebar1](/uploads/4b8d0eaa1b320c319239cb572932f740/sidebar1.gif)

See merge request !3547

app/assets/javascripts/merge_request_tabs.js.coffee

@@ -73,7 +73,8 @@ class @MergeRequestTabs
       @expandView()
     else if action == 'diffs'
       @loadDiff($target.attr('href'))
-      @shrinkView()
+      if bp? and bp.getBreakpointSize() isnt 'lg'
+        @shrinkView()
     else if action == 'builds'
       @loadBuilds($target.attr('href'))
       @expandView()