fix: dont warn about header if prop not changed

[WoLewicki]

Description

Added changes from https://github.com/react-navigation/react-navigation/blob/main/packages/native-stack/src/views/NativeStackView.tsx#L28 to display warning about header in modal only after the prop has been changed, so it will not display the warning if the user specified headerShown: true in the options for the screen.

Test code and steps to reproduce

Test800.tsx in TestsExample project.

Checklist

• Included code example that can be used to test this change
• Ensured that CI passes

[kacperkapusciak]

LGTM

[robinvw1]

Thanks @WoLewicki! I got this old warning Be aware that changing the visibility of header in modal on iOS will result in resetting the state of the screen. every time, without changing the headerShown prop. Hopefully this will land soon in the new release. :)