Fix card title h3 headers

app/assets/stylesheets/bootstrap_migration.scss

@@ -233,6 +233,13 @@ table {
   }
 }
 
+.card-header {
+  h3.card-title,
+  h4.card-title {
+    margin-top: 0;
+  }
+}
+
 .nav-tabs {
   // Override bootstrap's default border
   border-bottom: 0;

app/views/projects/protected_branches/shared/_branches_list.html.haml

 .protected-branches-list.js-protected-branches-list.qa-protected-branches-list
   - if @protected_branches.empty?
-    .card-header
-      %h3.card-title
+    .card-header.bg-white
+      %h3.card-title.mb-0
         Protected branch (#{@protected_branches_count})
     %p.settings-message.text-center
       There are currently no protected branches, protect a branch with the form above.