Less than two years after being disbarred by the Illinois Supreme Court, Robert C. Beck was sentenced in DuPage County to 4½ years in prison for stealing from his clients’ trust accounts — the same conduct that resulted in his disbarment.Beck, a former Wheaton lawyer, pleaded guilty before 18th Judicial Circuit Judge Liam C. Brennan in September to a felony count of theft between $500,000 and $1 million.His plea agreement stems from charges filed by the DuPage County State’s Attorney’s Office …