RootModel[str] cannot be parsed in cli with cli_enforce_required.

[plusls]

like #342

def test_cli_root_model():
    """Testing to pass string directly to root model by cli."""
    class Foo(RootModel[str]):
        root: str

    class Settings(BaseSettings, cli_enforce_required=True):
        foo: Foo
        plain: str

    TEST_STR = 'hello world'
    assert CliApp.run(Settings, cli_args=['--foo', TEST_STR, '--plain', TEST_STR]).model_dump() ==  {'foo': TEST_STR, 'plain': TEST_STR}

will cause system exit

[hramezani]

Thanks @plusls for the issue.

@kschwab please take a look when you have time.

[kschwab]

@hramezani @plusls opened #677 for resolution.

[hramezani]

Thanks @kschwab for the PR. @plusls Could you confirm the fix?