If newly created project includes Tests, hxs init fails.

When `hxs init` is run in a newly-created Xcode project which includes Tests, the ruby script that updates the `.pbxproj` fails.

To fix this, the methodology should be
* Create a new Xcode project with tests included
* Make a commit with the initialised project
* Apply the changes described in the blogpost (https://alt-romes.github.io/posts/2023-11-10-creating-a-macos-app-with-haskell-and-swift.html)
* Inspect the `git diff`
* Create another Xcode project without tests and commit the Xcode stuff
* Then run `hxs init`
* Investigate what differs from the diff produced by `hxs init` on a new project without tests and the manual change on a project with tests.
* Fix the ruby script that edits the pbxproj to account for what is needed when the project includes tests