By Jarrett Renshaw JEDDAH, Saudi Arabia (Reuters) – President Joe Biden and Saudi Crown Prince Mohammed bin Salman took a step to mending their troubled relationship with a fist bump, but the U.S. leader left the kingdom on Saturday with few big successes and doubts as to whether the visit was worth it. Biden’s four-day trip to Israel and Saudi Arabia, his first to the Middle East as president, aimed to reset ties with the Gulf Arab oil giant, demonstrate U.S. commitment to the region and counter the rising influence of Iran, Russia and China. But thorny optics overshadowed the Saudi leg as Bi…