Improve pipeline CSS

Use utility class for unstyled list
Remove direct child requirement for highlighting expanded job

app/assets/javascripts/pipelines/components/graph/stage_column_component.vue

@@ -61,7 +61,12 @@ export default {
 
     <div class="builds-container">
       <ul>
-        <li v-for="group in groups" :id="groupId(group)" :key="group.id" class="build">
+        <li
+          v-for="group in groups"
+          :id="groupId(group)"
+          :key="group.id"
+          class="build list-unstyled"
+        >
           <job-item
             v-if="group.size === 1"
             :job="group.jobs[0]"

app/assets/stylesheets/pages/pipelines.scss

@@ -494,10 +494,6 @@
         @include flat-connector-before;
       }
     }
-
-    li {
-      list-style: none;
-    }
   }
 
   .stage-name {
@@ -518,7 +514,7 @@
 
     .ci-job-dropdown-container {
       // highlight job whose dropdown is shown
-      &.dropdown.show > .build-content {
+      &.dropdown.show .build-content {
         background-color: $ci-action-dropdown-expanded-background;
 
         &:hover {