Fix incorrect redirect in response to unauthenticated API requests in limited federation mode (#34549)

app/controllers/api/base_controller.rb

@@ -141,6 +141,13 @@ class Api::BaseController < ApplicationController
     end
   end
 
+  # Redefine `require_functional!` to properly output JSON instead of HTML redirects
+  def require_functional!
+    return if current_user.functional?
+
+    require_user!
+  end
+
   def render_empty
     render json: {}, status: 200
   end