[BUG] Unable to add users on junos via napalm

Description
Then applying netusers state as described there https://docs.saltproject.io/en/latest/ref/states/all/salt.states.netusers.html got following error:

  File "/usr/lib/python3.6/site-packages/salt/state.py", line 2180, in call
    *cdata["args"], **cdata["kwargs"]
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 149, in __call__
    return self.loader.run(run_func, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 1201, in run
    return self._last_context.run(self._run_as, _func_or_method, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/contextvars/__init__.py", line 38, in run
    return callable(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 1216, in _run_as
    return _func_or_method(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 1249, in wrapper
    return f(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/states/netusers.py", line 327, in managed
    expected_users = _expand_users(users, defaults)
  File "/usr/lib/python3.6/site-packages/salt/states/netusers.py", line 74, in _expand_users
    expected_users.update(device_users)
AttributeError: 'NoneType' object has no attribute 'update'

Also if i try set users thru salt.modules.napalm_users.set_users got next error

sudo salt 'router1' users.set_users '{"micrea":{}}'
router1:
    ----------
    comment:
        Local file source set_users does not exist
    out:
        None
    result:
        False
ERROR: Minions returned with non-zero exit code

Setup
(Please provide relevant configs and/or SLS files (be sure to remove sensitive info. There is no general set-up of Salt.)

Juniper EX-3400

Please be as specific as possible and give set-up details.

• on-prem machine
• VM (Virtualbox, KVM, etc. please specify)
• VM running on a cloud service, please be explicit and add details
• container (Kubernetes, Docker, containerd, etc. please specify)
• or a combination, please be explicit
• jails if it is FreeBSD

Steps to Reproduce the behavior
users.sls

junos-users:
    netusers.managed:
         - users:
            admin:
                level: 15
                password: $1$knmhgPPv$g8745biu4rb.Zf.IT.F/U1
                sshkeys: []
            restricted:
                level: 1
                password: $1$j34j5k4b$4d5SVjTiz1l.Zf.IT.F/K7

/srv/pillar/juniper.sls

proxy:
  proxytype: napalm
  driver: junos
  ip: xx.xx.xx.xx
  username: user
  password: passwd

Expected behavior
Add/remove users from juniper config

Screenshots
If applicable, add screenshots to help explain your problem.

Versions Report

Salt Version:
          Salt: 3004.1
 
Dependency Versions:
          cffi: 1.11.5
      cherrypy: unknown
      dateutil: 2.6.1
     docker-py: Not Installed
         gitdb: Not Installed
     gitpython: Not Installed
        Jinja2: 2.10.1
       libgit2: Not Installed
      M2Crypto: 0.35.2
          Mako: Not Installed
       msgpack: 0.6.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     pycparser: 2.14
      pycrypto: Not Installed
  pycryptodome: Not Installed
        pygit2: Not Installed
        Python: 3.6.8 (default, Apr 12 2022, 06:55:39)
  python-gnupg: Not Installed
        PyYAML: 3.12
         PyZMQ: 19.0.0
         smmap: Not Installed
       timelib: Not Installed
       Tornado: 4.5.3
           ZMQ: 4.3.4
 
System Versions:
          dist: rocky 8.5 Green Obsidian
        locale: UTF-8
       machine: x86_64
       release: 4.18.0-348.7.1.el8_5.x86_64
        system: Linux
       version: Rocky Linux 8.5 Green Obsidian

Additional context
Add any other context about the problem here.

Start with salt/states/netusers.py, especially _expand_users and managed, then inspect the salt.modules.napalm_users.set_users entry point using the supplied users.sls and Junos proxy configuration. Reproduce the NoneType and local-file-source errors and trace how the Junos driver handles the requested users. Done means the state can add and remove the specified Junos users without either error.