Refactor the User MVVM by removing user variable

[SaturneV]

Description

In our current implementation, the difference between the _user and _currentUser variables in User MVVM makes almost no sense and complicates the integration of the viewmodel into our application. Given that the _user variable is not used and that our future integrations won't need it, it would be a good idea to refactor the viewmodel to use only the _currentUser variable in the viewmodel.

Tasks

• Remove the _user variable from the User viewmodel.
• Remove the related User viewmodel functions.
• Adapt all the projects files that use the _user variable
• Adapt all the projects tests files that use the _user variable