That’s the spirit. A top Biden official has all but admitted that the Democratic administration’s Justice Department sealed Spirit Airlines’ fate when it rejected a merger request — and suggested it was the wrong choice after the ultralow-cost airline shut down Saturday morning. Neera Tanden, who previously served as a senior advisor to former President Joe Biden, wondered whether a merger could have prevented the mass job losses. Sen. Elizabeth Warren (D-Mass.), meanwhile, tried to blame Spirit’s failure on President Trump — only to be called out for helping to kill the tieup with JetBlue. “Given the news today that…