fix: SearchBar.capitalization doesn't work as expected

[ndonkoHenri]

Resolves #5014

Test Code

import flet as ft


def main(page: ft.Page):
    anchor = ft.SearchBar(
        view_elevation=4,
        divider_color=ft.Colors.AMBER,
        on_change=lambda _: anchor.open_view(),
        on_submit=lambda _: anchor.open_view(),
        on_tap=lambda _: anchor.open_view(),
        capitalization=ft.TextCapitalization.CHARACTERS,
    )
    page.add(anchor)


ft.app(target=main)

Summary by Sourcery

Fixes the SearchBar.capitalization property to correctly apply the specified capitalization to the text entered in the search bar.

Bug Fixes:

• Fixes an issue where the SearchBar.capitalization property was not working as expected.
• Applies the correct capitalization to the text entered in the search bar based on the TextCapitalization enum.