Add test cases for creating projects via project templates
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### Problem
In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/110729 we removed support for legacy JSON formatted project import/export. We [noticed](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/110729#note_1338653225) that we don't have test coverage to ensure that creating projects from project templates works as expected.
### Proposal
Let's add automated tests for each of the project templates available under `projects/new#create_from_template`

issue