wsi/wayland: Use `wl_fixes` to destroy `wl_registry`

Destroy wl_registry objects using wayland/wayland!388 (merged).

Not sure how best to make use of unreleased libwayland features here. But anyway, this works as a placeholder, and can be tested by setting VK_ICD_FILENAMES, LD_LIBRARY_PATH, and __EGL_VENDOR_LIBRARY_FILENAMES.

I guess it will need to be made conditional libwayland version once the changes are merged in libwayland. Or the libwayland version with this feature would be a hard dependency.