Remove prepend-top-32 CSS class

This removes the prepend-top-32 CSS class
and replaces it with the gl-mt-7 utility
class from GitLab UI

app/assets/stylesheets/framework/common.scss

@@ -402,7 +402,6 @@ img.emoji {
 .prepend-top-default { margin-top: $gl-padding !important; }
 .prepend-top-16 { margin-top: 16px; }
 .prepend-top-20 { margin-top: 20px; }
-.prepend-top-32 { margin-top: 32px; }
 .prepend-left-5 { margin-left: 5px; }
 .prepend-left-10 { margin-left: 10px; }
 .prepend-left-15 { margin-left: 15px; }

app/views/projects/empty.html.haml

@@ -22,7 +22,7 @@
     = render 'stat_anchor_list', anchors: @project.empty_repo_statistics_buttons
 
   - if can?(current_user, :push_code, @project)
-    .empty-wrapper.prepend-top-32
+    .empty-wrapper.gl-mt-7
       %h3#repo-command-line-instructions.page-title-empty
         = _('Command line instructions')
       %p

app/views/projects/hook_logs/_index.html.haml

-.row.prepend-top-32.append-bottom-default
+.row.gl-mt-7.append-bottom-default
   .col-lg-3
     %h4.gl-mt-0
       Recent Deliveries