SS-1211 add e2e test to check that user cannot create a new project with the same name

[anondo1969]

Description

Source: https://scilifelab.atlassian.net/browse/SS-1211

1. Superuser can create project with existing project-name.
2. Other users can not create such project.

Checklist

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This is simply a reminder of what we are going to look for before merging your code.

• This pull request is against develop branch (not applicable for hotfixes)
• I have included a link to the issue on GitHub or JIRA (if any)
• I have included migration files (if there are changes to the model classes)
• I have included, reviewed and executed tests (unit and end2end) to complement my changes
• I have updated the related documentation (if necessary)
• I have added a reviewer for this pull request
• I have added myself as an author for this pull request
• In the case I have modified settings.py, then I have also updated the studio-settings-configmap.yaml file in serve-charts

Further comments

Anything else you think we should know before merging your code!

[akochari]

Great job! I just simplified the tests a bit.