gui-apps/hyprland-per-window-layout depends on virtual/rust

With slotting of rust this causes trouble. The ebuild inherits cargo, which already takes care of rust, so the dependency to virtual/rust must be dropped. That's all that needs to be done. The whole BDEPEND line is unnecessary. Tested locally.

Also while we're on the topic, there's a new, 2.13 version.

Best Regards,
Georgi