[BUG] Creating a mysql user with an invalid host parameter causes exception

Description
Creating a user that connects to a socket the host needs to be specified. Failing to do that causes an exception to fail due to an uninitialised variable

Setup
I use the Mysql formula with the following parameters.

    core_local:
      unix_socket: true
      host: 'localhost'
      databases:
        - database: '*'
          grants: ['file']
        - database: 'core'
          grants: ['select', 'insert', 'update', 'delete', 'create temporary tables', 'execute']

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
• classic packaging
• [ x] onedir packaging
• used bootstrap to install

Steps to Reproduce the behavior
Change the host from localhost to anything else and you get the below stack trace. Easy fix really.

          ID: mysql_user_core_local_127.0.0.1                                                                                                                                                                      
    Function: mysql_user.present                                                                                                                                                                                   
        Name: core_local                                                                                                                                                                                           
      Result: False                                                                                                                                                                                                
     Comment: An exception occurred in this state: Traceback (most recent call last):                                                                                                                              
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/state.py", line 2430, in call                                                                                                          
                  ret = self.states[cdata["full"]](                                                                                                                                                                
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 160, in __call__                                                                                                 
                  ret = self.loader.run(run_func, *args, **kwargs)                                                                                                                                                 
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 1233, in run                                                                                                     
                  return self._last_context.run(self._run_as, _func_or_method, *args, **kwargs)                                                                                                                    
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 1248, in _run_as
                  return _func_or_method(*args, **kwargs)
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 1281, in wrapper
                  return f(*args, **kwargs)
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/states/mysql_user.py", line 241, in present
                  if __salt__["mysql.user_create"](
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 160, in __call__
                  ret = self.loader.run(run_func, *args, **kwargs)
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 1233, in run
                  return self._last_context.run(self._run_as, _func_or_method, *args, **kwargs)
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/loader/lazy.py", line 1248, in _run_as
                  return _func_or_method(*args, **kwargs)
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/modules/mysql.py", line 1840, in user_create
                  qry, args = _mariadb_user_create(
                File "/opt/saltstack/salt/lib/python3.10/site-packages/salt/modules/mysql.py", line 1731, in _mariadb_user_create
                  __context__["mysql.error"] = err
              UnboundLocalError: local variable 'err' referenced before assignment

Expected behavior
It's expected to fail gracefully with useful information.

Versions Report

</details>

**Additional context**
Return text isn't allocated to the re var before returning it.

Start with salt/modules/mysql.py, especially user_create and _mariadb_user_create, then trace the call from salt/states/mysql_user.py. Reproduce the invalid-host case through mysql_user.present and verify that it fails gracefully with useful error information instead of an UnboundLocalError.