Remove "Previously known as"

Causes slow profile page loads. More we can clean up around this, but
this fixes the immediate user-facing issue.

Fixes #8204

app/views/user/show/_show_profile.html.erb

@@ -43,13 +43,6 @@
       <p><%= link_to _('Change your name'), edit_users_name_path %></p>
     <% end %>
 
-    <% if @display_user.active? && @display_user.safe_previous_names.any? %>
-      <p>
-        <%= _('Previously known as:') %>
-        <%= @display_user.safe_previous_names.to_sentence %>
-      </p>
-    <% end %>
-
     <p class="subtitle">
       <%= _('Joined {{site_name}} in {{year}}',
             :site_name => site_name,