Most exhibitions at St. George’s Sears Art Museum are months in the planning, with artworks that are meticulously hung and arranged. But instead immediacy was the inspiration for “COVID-19 Pops-Up in Art,” an exhibition in the Dixie State University museum’s foyer, says Kathy Cieslewicz, museum curator. Anchoring the show were artist Stewart Seidman’s series of eight large acrylic paintings about …