CHICAGO —- Failed Democratic presidential candidate Dean Phillips — who challenged President Joe Biden in this year’s primary to the guffaws and eye rolls of his party colleagues — is having a little moment at the Democratic National Convention. Phillips, who based his ultra-longshot campaign on the basis that Biden was too old and frail to beat Donald Trump, and that Democrats must nominate someone else, failed to win one Democratic primary contest. He wasn’t offered a prime-time speaking slot. But Biden withdrew last month, Kamala Harris is now the party’s presidential nominee and Phillips c…