ATLANTA — Georgia's highest court ruled Monday that a state law allowing courts to contract with private probation companies to supervise misdemeanor offenders is constitutional but does not allow for additional requirements beyond what is imposed by the courts. The Georgia Supreme Court was considering a case brought by a group of misdemeanor probationers in east Georgia who argued that Sentinel Offender Services and other private probation companies were illegally requiring electronic monitoring and extending sentences. The unanimous high court opinion partially affirmed and partially reversed lower-court rulings on the issue.