Just when we thought the world’s largest indoor theme park was hard to top, Dubai proves us wrong yet again. Its latest jaw-dropping megaproject is a tropical rainforest in a skyscraper hotel — another world-first for the emirate. The 7,000-square-meter rainforest will be part of the upcoming Rosemont Hotel and Residences Dubai, one of the properties under Hilton’s luxury independent brand Curio — A Collection by Hilton.The complex, expecting to welcome its first guests in…