BERLIN, June 21 (Reuters) - At a Berlin market stall operated by the nonprofit group Topio, volunteers assist visitors in disconnecting their phones from major U.S. tech ecosystems. Since Donald Trump returned to the U.S. presidency, the number of people seeking their service has increased. Interest in European-based digital alternatives has risen noticeably over recent months, according to market analysis company Similarweb. Users increasingly seek out email, messaging, and even search tools