By Guy Faulconbridge and Parisa Hafezi LONDON/DUBAI (Reuters) -Russian President Vladimir Putin had talks with Supreme Leader Ayatollah Ali Khamenei in Iran on Tuesday, the Kremlin leader’s first trip outside the former Soviet Union since Moscow’s Feb. 24 invasion of Ukraine. In Tehran, Putin also held his first face-to-face meeting since the invasion with a NATO leader, Turkey’s Tayyip Erdogan, to discuss a deal that would resume Ukraine’s Black Sea grain exports as well as the conflict in northern Syria. Putin’s trip, coming just days after U.S. President Joe Biden visited Israel and Saudi A…