fix: change scope setting for ngdk from 'window' to 'machine'

This commit changes the scope for `ngdk` from the default value `window`
to `machine` because `window` allows any project in a workspace to modify
the workspace settings, and `ngdk` could potentially be modified to point
to a compromised package.

Machine scope only allows the config value to be set in user or remote
settings.

Author: kyliau

package.json

@@ -33,7 +33,8 @@
             "null"
           ],
           "default": null,
-          "description": "Specifies the folder path to @angular/language-service."
+          "description": "Specifies the folder path to @angular/language-service.",
+          "scope": "machine"
         },
         "angular.log": {
           "type": "string",