Add fallback redirection when getting a webfinger query WEB_DOMAIN@WEB_DOMAIN (#28592)

app/controllers/well_known/webfinger_controller.rb

@@ -21,7 +21,7 @@ module WellKnown
       username = username_from_resource
 
       @account = begin
-        if username == Rails.configuration.x.local_domain
+        if username == Rails.configuration.x.local_domain || username == Rails.configuration.x.web_domain
           Account.representative
         else
           Account.find_local!(username)