feat: finish migration to new globals system for wireguard

modules/globals.nix

@@ -1,6 +1,5 @@
 {
   lib,
-  options,
   ...
 }:
 let
@@ -366,12 +365,5 @@ in
         };
       };
     };
-
-    _globalsDefs = mkOption {
-      type = types.unspecified;
-      default = options.globals.definitions;
-      readOnly = true;
-      internal = true;
-    };
   };
 }