A federal judge decided last week to deny a motion for dismissal in a lawsuit filed by The John Marshall Law School against an insurance company over the company’s refusal to cover an employee discrimination claim against the school.In April, John Marshall filed suit against Pittsburgh-based National Union Fire Insurance Co., in which it alleged that the company wrongfully denied the school coverage of a claim when a professor, Joel Cornwell, sued the school in an employee discrimination matter in 2013.In June, the …