U.S. Vice President Kamala Harris launched her campaign for president on Sunday after her running mate stepped aside, and it has reportedly led to the biggest fundraising day for Democrats all year. President Joe Biden announced earlier in the day that he would stand down from his political campaign, which cleared the way for Harris to secure endorsements from numerous Democratic lawmakers. One endorsement from a singer was considered the most important one she got all day. But there’s even more to the story, according to nonprofit fundraising platform ActBlue. Want more breaking political new…