test(packages/sui-test): fix custom studio-utils alias

[kikoruiz]

With this PR, it's possible to add custom aliases from the package.json config like this:

{
  "config": {
    "sui-test": {
      "client": {
        "alias": {
          "my-package": "path/to/my-package"
        }
      }
    }
  }
}