SAN DIEGO — For many it’s the sound of home. It’s the music their parents danced to at weddings, teenage siblings played to heal from a heartbreak and uncles sang out of tune to while drinking tequila. It can be cheerful, patriotic, sad, desperate and hopeful. Mariachi music transports many listeners to a memory of a country they left behind, a long lost love or happy times with family members and friends. For a while it seemed the music, along with the talented musicians who play it, were becoming another casualty of the coronavirus pandemic. Early last year numerous weddings, qui...