Add optional dependencies on polkit and .install like sway
c6350f92 dropped dependency on polkit, however either polkit or a enabled seatd.service is required for hyprland to function.
Polkit should be added to optdepends, and a .install file should be added like https://gitlab.archlinux.org/archlinux/packaging/packages/sway/-/blob/main/sway.install?ref_type=heads
While one can argue that these apply to every wlroots compositor and thus should be added to the wlroots package instead, hyprland bundles its own wlroots so...