SS-1432 remove_locust_users command fails to delete users from the database

[anondo1969]

Status

Ready for review.

Description

Fixing it by deleting the projects first.

Source: https://scilifelab.atlassian.net/browse/SS-1432

Types of changes

bugfix

Checklist

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• 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)
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• 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!

[anondo1969]

This PR is connected with #330 , which involves in changing the test data manager class in a different directory. So before #330 is merged, there will be error in checks. Thanks.