Allow scrolling within grouped pipelines

app/assets/stylesheets/pages/pipelines.scss

@@ -420,7 +420,11 @@
         left: auto;
         right: -197px;
         top: -9px;
-        max-height: 245px;
+
+        ul {
+          max-height: 245px;
+          overflow: auto;
+        }
 
         a {
           color: $gl-text-color;

app/views/projects/commit/_pipeline_status_group.html.haml

@@ -5,8 +5,9 @@
   %span.ci-status-text
     = name
   %span.badge= subject.size
-%ul.dropdown-menu.grouped-pipeline-dropdown
-  %li.arrow
-  - subject.each do |status|
-    %li
-      = render "projects/#{status.to_partial_path}_pipeline", subject: status
+.dropdown-menu.grouped-pipeline-dropdown
+  .arrow
+  %ul
+    - subject.each do |status|
+      %li
+        = render "projects/#{status.to_partial_path}_pipeline", subject: status