WASHINGTON — House Republican Leader Kevin McCarthy said Tuesday that he won’t support a proposal to form an independent, bipartisan commission to study the deadly Jan. 6 insurrection at the U.S. Capitol, almost certainly eroding GOP support ahead of a vote and positioning his party as opposed to investigations of the attack. McCarthy said he wanted the new panel to look beyond the violent uprising by supporters loyal to Donald Trump, who were trying to stop the certification of President Joe Biden’s election.