CHICAGO — Gov. Gavin Newsom said in the four weeks since Vice President Kamala Harris replaced President Biden at the top of the Democratic Party’s 2024 ticket, “everyone and their mother is jumping on to help.“Harris has been riding a wave of momentum as she has enjoyed a surge in polling and fundraising after Biden’s blockbuster announcement that he was ending his re-election bid for a second term in the White House.Biden’s disastrous performance against former President Trump in their late June debate fueled questions over whether the 81-year-old president had the physical and mental abilities to handle another four years in the White House and sparked a chorus of calls from within his own party to end his 2024 campaign.BIDEN PASSES TORCH TO HARRIS ON FIRST NIGHT OF DEMOCRATS’ CONVENTIONBiden eventually …