Having the same issue. It's a really bad workaround, I have thousands and thousands of files there, and when scrolling to select all the page crashes. Can't beleive there is no "empty deleted files" folder or something of the sort. Horrible user experience.
@El Wombat I was able to empty the trash through the Creative Cloud iOS app on my phone. They do have a empty trash button there and it works! Took me a loooooong time to find this solution, but it's simple and works!