Add `name` property to the `test-devices` API endpoint

The current implementation of the /apps/{app-slug}/test-devices endpoint does not return name property associated with a test device. However, this property does exists when you download list of test devices from the Team tab in your app.

The request is to add the name property to /apps/{app-slug}/test-devices. This will make registering devices, via fastlane tools for example, cleaner and easier.

Thanks for the #feature-request @mlego!