By James Oliphant and Kanishka Singh WASHINGTON (Reuters) – The panel probing the Jan. 6, 2021, assault on the U.S. Capitol plans to push its investigation further in the coming weeks, interviewing additional members of Donald Trump’s cabinet and his campaign, as well as U.S. Secret Service members, the committee’s vice chair said on Sunday. “We’re not finished yet,” Representative Liz Cheney, one of two Republicans on the U.S. House of Representatives’ select committee, told CNN’s “State of the Union.” In eight hearings over six weeks featuring testimony from former White House officials and …