fix: Automatically remove expired story mention (#5300)

When a user mentions the connected Instagram page in a story, the story's content is downloaded in Chatwoot, then if the user deletes the story, the content persists in the platform.

fixes: #5258

spec/models/message_spec.rb

@@ -180,4 +180,34 @@ RSpec.describe Message, type: :model do
       expect(message.email_notifiable_message?).to be true
     end
   end
+
+  context 'when facebook channel with unavailable story link' do
+    let(:instagram_message) { create(:message, :instagram_story_mention) }
+
+    before do
+      # stubbing the request to facebook api during the message creation
+      stub_request(:get, %r{https://graph.facebook.com/.*}).to_return(status: 200, body: {
+        story: { mention: { link: 'http://graph.facebook.com/test-story-mention', id: '17920786367196703' } },
+        from: { username: 'Sender-id-1', id: 'Sender-id-1' },
+        id: 'instagram-message-id-1234'
+      }.to_json, headers: {})
+    end
+
+    it 'deletes the attachment for deleted stories' do
+      expect(instagram_message.attachments.count).to eq 1
+      stub_request(:get, %r{https://graph.facebook.com/.*}).to_return(status: 404)
+      instagram_message.push_event_data
+      expect(instagram_message.reload.attachments.count).to eq 0
+    end
+
+    it 'deletes the attachment for expired stories' do
+      expect(instagram_message.attachments.count).to eq 1
+      # for expired stories, the link will be empty
+      stub_request(:get, %r{https://graph.facebook.com/.*}).to_return(status: 200, body: {
+        story: { mention: { link: '', id: '17920786367196703' } }
+      }.to_json, headers: {})
+      instagram_message.push_event_data
+      expect(instagram_message.reload.attachments.count).to eq 0
+    end
+  end
 end