Remove append-bottom-15 utility class

This removes the append-bottom-15 CSS
class and replaces it for the gl-mb-4
utility class from GitLab-UI

app/assets/javascripts/ide/components/commit_sidebar/actions.vue

@@ -70,7 +70,7 @@ export default {
 </script>
 
 <template>
-  <div class="append-bottom-15 ide-commit-options">
+  <div class="gl-mb-5 ide-commit-options">
     <radio-group
       :value="$options.commitToCurrentBranch"
       :disabled="!canPushToBranch"

app/assets/javascripts/ide/components/commit_sidebar/list_collapsed.vue

@@ -75,7 +75,7 @@ export default {
       :title="titleTooltip"
       data-container="body"
       data-placement="left"
-      class="append-bottom-15"
+      class="gl-mb-5"
     >
       <icon v-once :name="iconName" :size="18" />
     </div>

app/assets/stylesheets/framework/common.scss

@@ -412,7 +412,6 @@ img.emoji {
 .append-right-default { margin-right: $gl-padding; }
 .append-right-20 { margin-right: 20px; }
 .append-bottom-10 { margin-bottom: 10px; }
-.append-bottom-15 { margin-bottom: 15px; }
 .append-bottom-20 { margin-bottom: 20px; }
 .ml-10 { margin-left: 4.5rem; }
 .inline { display: inline-block; }