fix recursive UI

[adhami3310]

this is now possible

@dataclass
class File:
    name: str
    children: list["File"]


@rx.memo
def folder(file: rx.Var[File]) -> rx.Component:
    return rx.vstack(
        rx.heading(file.name),
        rx.box(
            rx.foreach(file.children, lambda f: folder(file=f)),
            padding_inline_start="1em",
        ),
    )


def index() -> rx.Component:
    return folder(
        file=File(
            "home",
            [
                File(
                    "documents",
                    [],
                ),
                File(
                    "downloads",
                    [
                        File("images", []),
                        File("videos", []),
                        File("music", []),
                    ],
                ),
                File("pictures", []),
            ],
        )
    )