After a short birthday trip to Italy, Selena Gomez (34) is back in front of the camera. The singer and actress was seen in a good mood this week on the set of the series "Only Murders in the Building" in London, where she has been shooting the sixth season for a few weeks, as Daily Mail reports. In her role as Mabel Mora she wore a bordeaux coat, combined with mini skirt, tights and boots – apparently autumn scenes were shot, although the waitin…