A Tunisian judge has jailed eight members of a police union for harming public security and disobedience after clashes with police forces who tried break up their sit-in protest, a union official said on Friday. Tension has been growing between police unions and the Interior Ministry. The unions accused the authorities of trying to stifle union activity, which it say is a valuable gain they achieved since the 2011 revolution. It comes as President Kais Saied faces widespread criticism that he is tightening his grip after he seized executive power last year, dissolved parliament, named a new el…