Donald Trump Jr. erupted in a profanity-filled tirade against Defense Secretary Lloyd Austin on social media on Thursday evening, demanding an end to U.S. support for Ukraine against Russian aggression. Trump Jr.’s remarks came in response to a right-wing account saying that former Fox News anchor Tucker Carlson “confirm[ed]” that Austin warned “your uncles, cousins and sons” might be sent to fight in Russia if Ukraine didn’t get the funding it needs. “How about Go F–k Yourself!!!” wrote Trump Jr. “America doesn’t need to keep funding an endless war with no path to victory.” POLL: Should Trum…