If accounts service is not yet running the name will not be registered
when we make our first call.

We call into AccountsService from our client code with a blocking call.
We then create a new QDBusAbstractInterface on a given service.

QDBusAbstractInterface::isValid effectively is just a check that the
service is registered. This might not be processed yet at the time we
call this. It isn't a helpful check, if it wasn't up the previous call
to fetch users would have failed. We can just remove it.

BUG: 429314