By Daniel Trotta (Reuters) – California Governor Gavin Newsom killed a bill that would have banned tackle football for kids under 12, as his veto threat led the sponsor of the bill to withdraw it from consideration on Wednesday. California would have been the first state in the U.S. to ban tackle football for kids, according to the nonprofit newsroom CalMatters, though legislators in several other states have introduced similar, unsuccessful bills out of concern that blows to the head in contact sports can cause brain injuries. State Assembly Member Kevin McCarty, a Democrat from Sacramento, h…