fix: Update Slack integration to fix message delivery issues (#6093)

spec/lib/integrations/slack/incoming_message_builder_spec.rb

@@ -12,6 +12,24 @@ describe Integrations::Slack::IncomingMessageBuilder do
       event_time: 1_588_623_033
     }
   end
+  let(:sub_type_message) do
+    {
+      team_id: 'TLST3048H',
+      api_app_id: 'A012S5UETV4',
+      event: message_event.merge({ type: 'message', subtype: 'bot_message' }),
+      type: 'event_callback',
+      event_time: 1_588_623_033
+    }
+  end
+  let(:message_without_user) do
+    {
+      team_id: 'TLST3048H',
+      api_app_id: 'A012S5UETV4',
+      event: message_event.merge({ type: 'message', user: nil }),
+      type: 'event_callback',
+      event_time: 1_588_623_033
+    }
+  end
   let(:message_with_attachments) { slack_attachment_stub }
   let(:message_without_thread_ts) { slack_message_stub_without_thread_ts }
   let(:verification_params) { slack_url_verification_stub }
@@ -81,6 +99,20 @@ describe Integrations::Slack::IncomingMessageBuilder do
         expect(conversation.messages.count).to eql(messages_count)
       end
 
+      it 'does not create message for message sub type events' do
+        messages_count = conversation.messages.count
+        builder = described_class.new(sub_type_message)
+        builder.perform
+        expect(conversation.messages.count).to eql(messages_count)
+      end
+
+      it 'does not create message if user is missing' do
+        messages_count = conversation.messages.count
+        builder = described_class.new(message_without_user)
+        builder.perform
+        expect(conversation.messages.count).to eql(messages_count)
+      end
+
       it 'does not create message for invalid event type and event files is not present' do
         messages_count = conversation.messages.count
         message_with_attachments[:event][:files] = nil