Preserve old redirect URLs

They may be cached for existing apps upgrading to 6.1. Follows up on rails#34477.

Author: georgeclaghorn

Diff for: activestorage/config/routes.rb

@@ -4,9 +4,11 @@
   scope ActiveStorage.routes_prefix do
     get "/blobs/redirect/:signed_id/*filename" => "active_storage/blobs/redirect#show", as: :rails_service_blob
     get "/blobs/proxy/:signed_id/*filename" => "active_storage/blobs/proxy#show", as: :rails_service_blob_proxy
+    get "/blobs/:signed_id/*filename" => "active_storage/blobs/redirect#show"
 
     get "/representations/redirect/:signed_blob_id/:variation_key/*filename" => "active_storage/representations/redirect#show", as: :rails_blob_representation
     get "/representations/proxy/:signed_blob_id/:variation_key/*filename" => "active_storage/representations/proxy#show", as: :rails_blob_representation_proxy
+    get "/representations/:signed_blob_id/:variation_key/*filename" => "active_storage/representations/redirect#show"
 
     get  "/disk/:encoded_key/*filename" => "active_storage/disk#show", as: :rails_disk_service
     put  "/disk/:encoded_token" => "active_storage/disk#update", as: :update_rails_disk_service