The Dolphins are pushing back on claims from Brian Flores that he was asked to sign a non-disclosure agreement by owner Stephen Ross after his firing in January. In an excerpt from an interview with Bryant Gumbel set to air on HBO’s “Real Sports with Bryant Gumbel” at 10 p.m. Tuesday, Flores says he did not sign a “separation agreement,” which is preventing him from collecting “millions of dollars” on the final two years of his contract, according to his lawyer John Elefterakis. Flores made similar comments in an interview on the “I Am Athlete” podcast released Monday. “Just signing that, you …