win_user: Clean up parameter handling and $result hash (#21375)
win_user: Clean up parameter handling and $result hash (#21375)

* win_user: Clean up parameter handling and $result hash

Changes include:
- Use of Get-AnsibleParam and parameter types/validateset
- Removed parameter validation
- Replace $result PSObject with normal hash

* Revert to original formatting

* Parameter "groups" is a list

thaim/ansible,thaim/ansible