Vice President Kamala Harris rolled out a promise to stomp out taxes on tips during a campaign stop in Las Vegas Saturday — prompting former President Donald Trump to rip her for “copying” one if his signature proposals. Though she spent a significant portion of her talk ripping Trump, the Democratic presidential nominee regurgitated one of his signature ideas at the top of her stump speech at the battleground state. “It is my promise to everyone here, when I am President, we will continue our fight for working families of…