UserManagementProvider constructor Null safety

1. smooth_app
2. user_management_provider
3. UserManagementProvider
4. UserManagementProvider constructor

UserManagementProvider class

1. Constructors
2. UserManagementProvider
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. credentialsInStorage
8. login
9. logout
10. noSuchMethod
11. putUser
12. toString
13. Operators
14. operator ==
15. Static methods
16. mountCredentials