Refactor by removing duplicated projects from specs

What does this MR do and why?

Although the best case would be to have both project and merge request as a single instance and set with let_it_be, this change removes duplicated projects from specs. In more details:

1. It removes all duplications of project.
2. It moves the single project instance to the top level.
3. Removes top-level subject which was being overridden and only used once.

Related issue: #241497 (closed)

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