[ENG-3793] convert event return types to type hints

[adhami3310]

import dataclasses
import reflex as rx

@dataclasses.dataclass
class Guy:
    name: str

class State(rx.State):
    """State for the TestApp app."""

    @rx.event
    def on_event(self, payload: Guy):
        print(f"Hello {payload.name}!")

app = rx.App()

@app.add_page
def index():
    return rx.vstack(
        rx.button(
            on_click=State.on_event(Guy("Alice")),
        ),
    )

[adhami3310]

Fixes #4264

[adhami3310]

@benedikt-bartscher how would you imagine hooking into this system? maybe

@deserializer
def deserialize_datetime(value: str) -> datetime:
    ...

[linear[bot]]

ENG-3793 Event Handlers should accept rx.Base arguments

[adhami3310]

In case we want to improve the system, we can do so in later PRs o7

[masenf]

This is a breaking change, technically, but i think it breaks in the right way because what was there before was incorrect