Iconic songwriter Diane Warrenwas among the stars nominated for an Oscar this year, and insiders said she threw a conniption when her name wasn’t even mentioned when Ariana Grandepresented Best Original Song at the 96th Academy Awards ceremony. RadarOnline.com has learned that eyewitnesses claimed they saw Warren throw a “mini tantrum” when the pop star skipped the names and credits of all five best original song nominees and went straight into revealingBillie Eilish as the winner for her hit track “What Was I Made For?” for the Barbie movie. Warren was among those up for a prize this year for…