PHILADELPHIA — Starbucks wants to add training for store managers on “unconscious bias,” CEO Kevin Johnson said Monday, as activists held more protests at a Philadelphia store where two black men were arrested when employees said they were trespassing.Johnson, who has called the arrests “reprehensible,” arrived in Philadelphia this weekend after video of the arrests gained traction online. He said he hopes to meet with the two men in the next couple of days and apologize to them face-to-face …