Remove alchemy/admin/all.js from admin layout

No more sprockets file that needs to be compile in the host app for you, sorry.
Use importmaps instead if you want to add JS to the Alchemy admin.

app/views/layouts/alchemy/admin.html.erb

@@ -22,7 +22,6 @@
     </script>
     <%= render 'alchemy/admin/tinymce/setup' %>
     <%= render 'alchemy/admin/partials/routes' %>
-    <%= javascript_include_tag('alchemy/admin/all', 'data-turbo-track' => true) %>
     <%= javascript_importmap_tags("alchemy_admin", importmap: Alchemy.importmap) %>
     <% Alchemy.admin_js_imports.each do |path| %>
       <script type="module">