Do not use ActiveStorage variants, process original avatar

Variants are currently broken. So we process the original file with the
most common avatar dimensions and stripping metadata, then hash and
upload only that version.

app/views/settings/_profile.html.erb

@@ -38,8 +38,7 @@
       <div class="flex items-center gap-6">
         <% if @user.avatar.attached? %>
           <p class="flex-none">
-            <%= image_tag @user.avatar_variant(size: :medium),
-              class: "h-24 w-24 rounded-lg" %>
+            <%= image_tag image_url_for(@user.avatar), class: "h-24 w-24 rounded-lg" %>
           </p>
         <% end %>
         <div class="grow">