Revert "Merge pull request solidusio#6122 from mamhoff/create-manifest-js-in-generated-apps"

This reverts commit bec42f6, reversing
changes made to 37a5c8a.

Author: mamhoff

core/lib/generators/solidus/install/install_generator.rb

@@ -121,9 +121,6 @@ def install_routes
 
     def add_files
       template 'config/initializers/spree.rb.tt', 'config/initializers/spree.rb'
-      if Rails.version >= "8.0"
-        template "app/assets/config/manifest.js", "app/assets/config/manifest.js", force: true
-      end
     end
 
     def install_file_attachment