The 50th home run ball from Los Angeles Dodgers star Shohei Ohtani’s historic 50-50 season went up for auction Friday after its ownership was challenged in a lawsuit filed earlier this week. Bidding topped $1 million only hours after the auction began online with a starting bid of $500,000, according to Goldin Auctions LLC based in New Jersey. Ohtani hit the milestone home run and marked a 50th stolen base against the Miami Marlins on Sept. 19, which made the 30-year-old Japanese the first Major League Baseball player to pull off both in one season. While the name of the seller has not been ma…