test: hide channel input in update mutation

Author: barnabasJ

test/support/resources/channel/channel_simple.ex

@@ -15,7 +15,10 @@ defmodule AshGraphql.Test.ChannelSimple do
     type :channel_simple
 
     mutations do
-      update :update_channel, :update_channel, read_action: :read_channel, identity: false
+      update :update_channel, :update_channel,
+        read_action: :read_channel,
+        identity: false,
+        hide_inputs: [:channel]
     end
   end