`Control.parent` property

[ndonkoHenri]

Closes #952

• Issue TBF: The tiles created on_click of the first tile have no parent (None) although they all live in thesame Column.

Test Code:

import flet as ft

def main(page: ft.Page):
    def handle_add_to_parent(e: ft.ControlEvent):
        c: ft.Control = e.control
        print(f"The clicked {c.__class__.__name__} has parent {c.parent.__class__.__name__}")
        if isinstance(c.parent, ft.Column):
            c.parent.controls.append(
                ft.ListTile(
                    leading=ft.Icon(ft.icons.ALBUM),
                    trailing=ft.IconButton(ft.icons.DELETE, on_click=handle_add_to_parent),
                    title=ft.Text("The Enchanted Nightingale"),
                    subtitle=ft.Text(
                        "Music by Julie Gable. Lyrics by Sidney Stein."
                    ),
                    on_click=handle_add_to_parent
                )
            )
            page.update()


    page.add(
        ft.Column(
            [
                ft.ListTile(
                    leading=ft.Icon(ft.icons.ALBUM),
                    trailing=ft.IconButton(ft.icons.DELETE, on_click=handle_add_to_parent),
                    title=ft.Text("The Enchanted Nightingale"),
                    subtitle=ft.Text(
                        "Music by Julie Gable. Lyrics by Sidney Stein."
                    ),
                    on_click=handle_add_to_parent
                ),
            ]
        )
    )

ft.app(target=main)