use webhook urls instead of encrypted configs

app/controllers/testing_api_settings_controller.rb

@@ -4,9 +4,8 @@ class TestingApiSettingsController < ApplicationController
   def index
     authorize!(:manage, current_user.access_token)
 
-    @webhook_config =
-      current_account.encrypted_configs.find_or_initialize_by(key: EncryptedConfig::WEBHOOK_URL_KEY)
+    @webhook_url = current_account.webhook_urls.first_or_initialize
 
-    authorize!(:manage, @webhook_config)
+    authorize!(:manage, @webhook_url)
   end
 end