By James Oliphant and Kanishka Singh WASHINGTON, July 24 (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...