Removing deprecation warning (#16572)

Prior to this commit, I saw the following in the Rails test log:

```
DEPRECATION WARNING: 'include Pundit' is deprecated. Please use 'include Pundit::Authorization' instead.
 (called from include at ./app/controllers/application_controller.rb:12)
 ```

app/controllers/api/v0/listings_controller.rb

@@ -1,7 +1,7 @@
 module Api
   module V0
     class ListingsController < ApiController
-      include Pundit
+      include Pundit::Authorization
       include ListingsToolkit
 
       # actions `create` and `update` are defined in the module `ListingsToolkit`,

app/controllers/application_controller.rb

@@ -9,7 +9,7 @@ class ApplicationController < ActionController::Base
 
   include SessionCurrentUser
   include ValidRequest
-  include Pundit
+  include Pundit::Authorization
   include CachingHeaders
   include ImageUploads
   include DevelopmentDependencyChecks if Rails.env.development?
@@ -74,7 +74,7 @@ class ApplicationController < ActionController::Base
 
   def not_authorized
     render json: { error: I18n.t("application_controller.not_authorized") }, status: :unauthorized
-    raise NotAuthorizedError, "Unauthorized"
+    raise Pundit::NotAuthorizedError, "Unauthorized"
   end
 
   def bad_request