networkmanager: fix dispatcher scripts (#24507)

networkmanager used `source` to mean `text` and wrote dispatcher scripts with the default mode (0666), which means networkmanager wouldn't call them.

nixos/modules/services/networking/networkmanager.nix

@@ -162,9 +162,9 @@ in {
         type = types.listOf (types.submodule {
           options = {
             source = mkOption {
-              type = types.str;
+              type = types.path;
               description = ''
-                A script source.
+                A script.
               '';
             };
 
@@ -224,7 +224,7 @@ in {
              target = "NetworkManager/dispatcher.d/02overridedns";
            }
       ++ lib.imap (i: s: {
-        text = s.source;
+        inherit (s) source;
         target = "NetworkManager/dispatcher.d/${dispatcherTypesSubdirMap.${s.type}}03userscript${lib.fixedWidthNumber 4 i}";
       }) cfg.dispatcherScripts;