Write Tests for the 4 safe areas 🧪

## Bug description
Write tests for making sure that the 4 safe areas to edit the generated output works fine without the generator overwriting the changes

## [Understand the feature here](https://github.com/YassinEldeeb/prisma-tgql-types-gen#how-to-edit-the-generated-code-without-being-overwritten-by-the-generator)