Rep. James Comer won a victory against Hunter Biden Friday when the president’s legally beleaguered son agreed to testify behind closed House Oversight Committee doors, according to a new report. That didn’t stop Hunter Biden’s attorneys from slapping back at House Republicans over a subpoena they argued wasn’t proper or legally valid, the Messenger reports. “If you issue a new proper subpoena, now that there is a duly authorized impeachment inquiry, Mr. Biden will comply for a hearing or deposition,” attorney Abbe Lowell reportedly said in a letter to Republicans leading the impeach-Joe-Biden…