[REF-1425] Always capitalize tag of StatefulComponent

[masenf]

Lowercase tags in JSX are rendered as plain HTML, so the code hash suffix breaks the element.

import reflex as rx


class State(rx.State):
    v: str = "foo"


def index() -> rx.Component:
    return rx.el.div(State.v)


app = rx.App()
app.add_page(index)
app.compile()

should show "foo"