EXCLUSIVE: BYRON CENTER, Mich. — Donald Trump’s running mate has an answer to the blunt advice from allies and fellow Republicans that the former president should stick to policy and messaging instead of questioning Vice President Kamala Harris’ crowd sizes at her rallies, her race or attacks on her intellect.“I think one of the things people actually love about Donald Trump in politics is he’s not unwilling to speak off the cuff. He says what’s actually on his mind. He’s not always filtered. I think that’s a good thing and part of his appeal,” GOP vice presidential nominee Sen. JD Vance, R‑Ohio, said Wednesday in a national exclusive interview with Fox News Digital.But Vance, speaking ahead of a campaign event in battleground Michig …