That wasn't about the theme music, it was about the suspense music that "attacked" Ruby.
TV Tropes
has a list of the many times
Doctor Who has broken the fourth wall, though it's mainly just instances of the Doctor or other characters looking at the camera. Capaldi did it repeatedly in episodes like "Listen" and "Before the Flood" where he monologued to the audience. And there was that bit in "The Caves of Androzani" where the villain's actor misunderstood a stage direction and soliloquized directly to the camera, but the director liked it and told him to keep doing it.