nixos/display-managers: install sessionData.desktops

Fixes #100108

(cherry picked from commit 3cd2b59)

nixos/modules/services/x11/display-managers/default.nix

@@ -464,6 +464,13 @@ in
             )
             [dms wms]
           );
+
+    # Make xsessions and wayland sessions installed at
+    # /run/current-system/sw/share as some programs
+    # have behavior that depends on them being installed
+    environment.systemPackages = [
+      cfg.displayManager.sessionData.desktops
+    ];
   };
 
   imports = [