### Summary
This pull request addresses the issue described in #9232, where
attempting to delete a user account results in a `TypeError: Cannot read
properties of undefined (reading 'dataSourceService')`.
### Changes Made
- Fixed the `this` context issue in the `deleteUserFromWorkspace` method
by ensuring it is correctly bound.
- Updated the `deleteUser` method to use a bound function when calling
`deleteUserFromWorkspace`.
### Linked Issue
This pull request fixes#9232.
### Additional Notes
- Please review the changes carefully to ensure no unintended side
effects in the user or workspace deletion process.
- Suggestions for further improvement are welcome.
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Co-authored-by: Lucas Bordeau <bordeau.lucas@gmail.com>
Co-authored-by: Weiko <corentin@twenty.com>