on_window_event isnt handled after page navigation

[LipmanJon]

Description

It seems that on_window_event doesn't trigger after navigating to a new view.
It seems to be a regression - on version 0.10.3 it works, but breaks on 0.12.0.

Code example to reproduce the issue:

import flet as ft


def main(page: ft.Page):
    page.title = "Routes Example"

    def route_change(route):
        page.views.clear()
        page.views.append(
            ft.View(
                "/",
                [
                    ft.AppBar(title=ft.Text("Flet app"), bgcolor=ft.colors.SURFACE_VARIANT),
                    ft.ElevatedButton("Visit Store", on_click=lambda _: page.go("/store")),
                ],
            )
        )
        if page.route == "/store":
            page.views.append(
                ft.View(
                    "/store",
                    [
                        ft.AppBar(title=ft.Text("Store"), bgcolor=ft.colors.SURFACE_VARIANT),
                        ft.ElevatedButton("Go Home", on_click=lambda _: page.go("/")),
                    ],
                )
            )
        page.update()

    def view_pop(view):
        page.views.pop()
        top_view = page.views[-1]
        page.go(top_view.route)

    def window_event(e):
        print(f"window event: {e}")
        if e.data == "close":
            page.window_destroy()

    page.window_prevent_close = True
    page.on_window_event = window_event

    page.on_route_change = route_change
    page.on_view_pop = view_pop
    page.go(page.route)


if __name__ == '__main__':
    ft.app(target=main)

Describe the results you received:
Original view allows to exit, but once a new view is appeneded then the window X exit button has no effect and doesnt trigger the on_window_event func.
Navigating back to the home view unblocks the exit button.

Describe the results you expected:
Exit should work regardless of view added.

Additional information you deem important (e.g. issue happens only occasionally):
Version 0.10.3 doesn't have this issue

Flet version (pip show flet):

0.12.0

Operating system:
Reproduced on macos + windows 10

Additional environment details:

[LipmanJon]

@DanielShwartz1 @Mache-Hoffman
Follow if interested

[FeodorFitsner]

Related to #2082. Working on a fix.