replace all instances of "ends_with?" with "end_with?" (#15745)

The "ends_with?" method is just a Rails alias of Ruby's "end_with?" method.
Using the latter makes the code less brittle.

app/controllers/application_controller.rb

@@ -43,7 +43,7 @@ class ApplicationController < ActionController::Base
   private
 
   def https_enabled?
-    Rails.env.production? && !request.path.start_with?('/health') && !request.headers["Host"].ends_with?(".onion")
+    Rails.env.production? && !request.path.start_with?('/health') && !request.headers["Host"].end_with?(".onion")
   end
 
   def authorized_fetch_mode?