After a user assigned as a budget admin deletes their account or gets blocked by
a moderator, the application throws an exception while loading the admin
investment index page.
As an erased user is not really deleted and neither its associated roles, the
application was failing when trying to sort and administration without a
username. In this case, the application was throwing an `ArgumentError:
comparison of NilClass with String failed` exception.
As a blocked user is not deleted or its roles, the application failed when trying
to access the user name through the delegation in the Administrator. In this
case, the application was throwing a `NoMethodError: undefined method `name' for
nil:NilClass` exception.
We check the changes have been saved and we check recommendations have
been disabled after visiting the debates and proposals pages. The
latter helps us avoid accessing the database after the process running
the browser has been started.
