DUBAI (Reuters) -World leaders descended on the United Arab Emirates on Sunday to offer condolences to new leader Sheikh Mohammed bin Zayed al-Nahyan on the death of his half-brother President Khalifa bin Zayed in a show of support to a key regional player. Sheikh Mohammed, now ruler of wealthy Abu Dhabi emirate, steered the Western-allied Gulf state, an OPEC oil producer and regional business hub, for years before being named the UAE’s third president by a federal supreme council on Saturday. French President Emmanuel Macron, whose country holds lucrative business and military ties with the U…