Suppress a RuboCop offense

Follow up to rubocop/rubocop#10312.

This commit suppresses the following RuboCop offense.

```console
% bundle exec rubocop -a
(snip)

lib/rubocop/cop/rails/http_positional_arguments.rb:70:87: C: [Corrected]
InternalAffairs/RedundantMethodDispatchNode: Remove the redundant
send_node.
          !!node.each_ancestor(:block).detect { |block|
          ROUTING_METHODS.include?(block.send_node.method_name) }
                                        ^^^^^^^^^^

227 files inspected, 1 offense detected, 1 offense corrected
```

Author: koic

lib/rubocop/cop/rails/http_positional_arguments.rb

@@ -67,7 +67,7 @@ def on_send(node)
         private
 
         def in_routing_block?(node)
-          !!node.each_ancestor(:block).detect { |block| ROUTING_METHODS.include?(block.send_node.method_name) }
+          !!node.each_ancestor(:block).detect { |block| ROUTING_METHODS.include?(block.method_name) }
         end
 
         def needs_conversion?(data)