The stage is set for the highly anticipated grand finale of “México Canta,” a singing competition akin to “American Idol” with one overriding rule: Songs that glorify the lives of cartels, violence or drug trafficking are not allowed. The finals of “México Canta por la paz y contra las adicciones” (“Mexico Sings for Peace and Against Addiction”) will be held Sunday night at the Esperanza Iris City Theater in Mexico City and televised live. A binational initiative from the Mexican government, the contest concludes after months of auditions and semifinals throughout the United States and Mexico. “México Canta” drew more than 15,000 applicants, ranging in age from 18 to 34, with eligibility extending to those singing in Spanish, Indigenous languages or Spanglish. Set against the backdrop of Mexico’s current musical culture — where the controversial “narco-corrido” genre (or corridos tumbados) has dominated charts with its odes to the drug trade — “México Canta” set out with a mission.