Fix confirmation redirect to app without Location header (#18523)

app/controllers/auth/confirmations_controller.rb

@@ -40,7 +40,7 @@ class Auth::ConfirmationsController < Devise::ConfirmationsController
 
   def after_confirmation_path_for(_resource_name, user)
     if user.created_by_application && truthy_param?(:redirect_to_app)
-      user.created_by_application.redirect_uri
+      user.created_by_application.confirmation_redirect_uri
     else
       super
     end

app/lib/application_extension.rb

@@ -12,4 +12,8 @@ module ApplicationExtension
   def most_recently_used_access_token
     @most_recently_used_access_token ||= access_tokens.where.not(last_used_at: nil).order(last_used_at: :desc).first
   end
+
+  def confirmation_redirect_uri
+    redirect_uri.lines.first.strip
+  end
 end