FIX: include silence_reason when admin sees user (#31493)

Small regression created in this PR
https://github.com/discourse/discourse/pull/30635

The reason is included only when `include_silence_reason` option is
included.

app/controllers/admin/users_controller.rb

@@ -50,6 +50,7 @@ class Admin::UsersController < Admin::StaffController
       AdminDetailedUserSerializer,
       root: false,
       similar_users_count: @user.similar_users.count,
+      include_silence_reason: true,
     )
   end