By Humeyra Pamuk ABU DHABI (Reuters) -President Joe Biden sent a high-powered U.S. delegation to the United Arab Emirates on Monday to offer condolences after the death of its ruler, in an apparent bid to repair frayed ties with Gulf Arab allies. Washington’s desire to improve relations with Gulf monarchies has become more urgent following Russia’s invasion of Ukraine, which highlighted the relevance of Gulf oil producers as Europe looks to cut its energy dependence on Russia. Gulf states have so far refused to take sides in the Ukraine conflict. OPEC heavyweights Saudi Arabia and the UAE have…