Fix: slack repeated callback event message for attached files (#4610)

spec/lib/integrations/slack/incoming_message_builder_spec.rb

@@ -71,6 +71,18 @@ describe Integrations::Slack::IncomingMessageBuilder do
         expect(conversation.messages.last.content).to eql('this is test https://chatwoot.com Hey @Sojan Test again')
         expect(conversation.messages.last.attachments).to be_any
       end
+
+      it 'ignore message if it is postback of CW attachment message' do
+        expect(hook).not_to eq nil
+        messages_count = conversation.messages.count
+        message_with_attachments[:event][:text] = 'Attached File!'
+        builder = described_class.new(message_with_attachments)
+
+        allow(builder).to receive(:sender).and_return(nil)
+        builder.perform
+
+        expect(conversation.messages.count).to eql(messages_count)
+      end
     end
   end
 end