Omar Marques | Lightrocket | Getty ImagesLONDON — Britain's competition regulator on Thursday launched an investigation into Apple and Google's huge mobile ecosystems to determine whether the tech titans are in breach of the U.K.'s strict new digital competition rules.The U.K. Competition and Markets Authority said it was opening dual probes into both U.S. tech giants to assess whether they hold "strategic market status" in their respective mobile ecosystems, including operating systems, app sto...