Chore: Fix duplicated project name on create project structure

[iLLiCiTiT]

Changelog Description

Small fix in project folders. It is not used same variable name to change values which breaks values on any next loop.

Additional info

Avoid reusing clean_items variable during for loop.

Testing notes:

1. Keep __project_root__ in folder structure settings.
2. Create a project and make sure it has more than one root.
3. Run create folders action (e.g. in Project manager in OpenPype or action in ftrack).

[ynbot]

Task linked: OP-7514 Multiroot folder structure