There will be no modeling of prison stripes for Naomi Campbell. The mercurial model, 29, pleaded guilty in a Toronto courtroom yesterday to a charge of assaulting her assistant on the movie set of “Prisoner of Love,” which was filmed in Canada in 1998. Campbell is expected to escape punishment and a criminal record, but the ex-assistant, Georgina Galanis, is suing her for $2 million, claiming Campbell hit her twice in the head with a telephone, punched her shoulder twice, grabbed her neck and violently shook her head. Campbell did not attend the court hearing on Wednesday, and her plea was entered by her lawyer. Under an agreement worked out with the prosecution, she expressed remorse for the attack.