Fix IDE dropdowns not showing up

**How?**
Reverts part of [the MR][1] that introduced
this regression.

**Why?**
This was caused by some bootstrap utility
class silliness that adds !important to all of
its utilities.

[1]: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/24264

app/assets/javascripts/ide/components/new_dropdown/index.vue

@@ -51,7 +51,7 @@ export default {
 </script>
 
 <template>
-  <div class="ide-new-btn d-none">
+  <div class="ide-new-btn">
     <div
       :class="{
         show: isOpen,

app/assets/stylesheets/page_bundles/ide.scss

@@ -1224,6 +1224,8 @@ $ide-commit-header-height: 48px;
 }
 
 .ide-new-btn {
+  display: none;
+
   .btn {
     padding: 2px 5px;
   }