RICHMOND, Va.—School mask mandates in Virginia would end on March 1 if the General Assembly adopts amendments made by Republican Gov. Glenn Youngkin to just-passed legislation on the issue. The legislature passed a bill Monday giving parents and students the ability to opt out of mandates imposed by local school boards. But the legislation would not have taken effect until July 1. On Monday night, Youngkin added an emergency clause to the legislation that allows it to take effect immediately upon passage. He also added a provision giving school districts until March 1 to develop plans to comply with the law. The amended legislation now must pass both legislative chambers on a majority vote. The bill’s supporters have expressed optimism that the amended bill can be passed by the legislature in a matter of days. One other provision added by Youngkin seeks to clarify that the bill does not restrict …