Sara Bareilles won’t have to “Waitress” this year. The two-time Grammy winner just extended her forthcoming ‘The Good Grief Tour’ in support of her forthcoming record with the same name. She’ll now play 26 concerts at music halls, theatres, performing arts centers and auditoriums all over North America from early September through late October. That includes two concerts at NYC’s Radio City Music Hall. Those gigs are slated to take place: Friday, Sept. 18 8 p.m. Saturday, Sept. 19 8 p.m. “I am