Don't require user manager to support user login in AuthenticateLocalAsync

For `UserManager.SupportsUserLogin` to be `true`, the `UserStore` needs to implement `IUserLoginStore`. This interface "maps users to login providers, i.e. Google, Facebook, ..." according to its documentation.

AFAIK, this should not be needed when authenticating locally. Hence, you should change the `UserManager` requirement to be `UserManager.SupportsUserPassword`, as the `UserStore` needs to implement the  `IUserPasswordStore` interface in order for the `UserManager.CheckPasswordAsync` call to work.