Bug - Flourish include expects only valid JSON but shared messaging API with ads

[LilyL0u]

https://www.test.bbc.com/mundo/23263889

I had put a Flourish include on this test page. It was causing this application error to fail the E2E tests:

With some digging by @andrewscfc, we found that the message.event is expecting JSON but it is also being used by ads on that page, and they are not sending valid json. This is why we get an unexpected token of a letter, and it varies what that letter is; that letter is what is being received first instead of the valid JSON opener {.

Now I am sure @andrewscfc can explain this better. If necessary I can get screenshots to give more detail.

I can put the include back in if it is needed for fixing the bug, but it does cause application errors in the simorgh pipeline e2es.