Update ruby ffi for upb_Message_DiscardUnknown.

#test-continuous

PiperOrigin-RevId: 713376224

ruby/lib/google/protobuf/ffi/message.rb

@@ -22,7 +22,7 @@ class FFI
       attach_function :decode_message,          :upb_Decode,                  [:binary_string, :size_t, :Message, MiniTable.by_ref, :ExtensionRegistry, :int, Internal::Arena], DecodeStatus
       attach_function :get_mutable_message,     :upb_Message_Mutable,         [:Message, FieldDescriptor, Internal::Arena], MutableMessageValue.by_value
       attach_function :get_message_which_oneof, :upb_Message_WhichOneofByDef, [:Message, OneofDescriptor], FieldDescriptor
-      attach_function :message_discard_unknown, :upb_Message_DiscardUnknown,  [:Message, Descriptor, :int], :bool
+      attach_function :message_discard_unknown, :upb_Message_DiscardUnknown,  [:Message, Descriptor, :DefPool, :int], :bool
       attach_function :message_next,            :upb_Message_Next,            [:Message, Descriptor, :DefPool, :FieldDefPointer, MessageValue.by_ref, :pointer], :bool
       attach_function :message_freeze,          :upb_Message_Freeze,          [:Message, MiniTable.by_ref], :void
       attach_function :message_frozen?,         :upb_Message_IsFrozen,        [:Message], :bool

ruby/lib/google/protobuf_ffi.rb

@@ -42,7 +42,8 @@ def self.deep_copy(object)
     def self.discard_unknown(message)
       raise FrozenError if message.frozen?
       raise ArgumentError.new "Expected message, got #{message.class} instead." if message.instance_variable_get(:@msg).nil?
-      unless Google::Protobuf::FFI.message_discard_unknown(message.instance_variable_get(:@msg), message.class.descriptor, 128)
+      pool_def = message.class.descriptor.instance_variable_get(:@descriptor_pool).descriptor_pool
+      unless Google::Protobuf::FFI.message_discard_unknown(message.instance_variable_get(:@msg), message.class.descriptor, pool_def, 128)
         raise RuntimeError.new "Messages nested too deeply."
       end
       nil