[iOS] URL handler do not receive data from external apps via Universal Link

A user has encountered an issue with Universal Links in an iOS app after upgrading from Qt 6.5.8 to Qt 6.8.0-6.8.3. The app, which relies on a QDesktopServices::setUrlHandler to respond to Universal Link launches, no longer updates the text on its window as expected with the received URL.

Environment
Qt Versions: 6.5.8 (works), 6.8.0–6.8.3 (not working as expected)

Xcode: 16.2

iOS: 18.3

Problem Description
The app is triggered via a Universal Link.

In Qt 6.5.8, a URL handler receives the URL and updates the display text correctly (changing from https://initial.value to the target URL).

In Qt 6.8.x, although the app is launched via the Universal Link, the handler is not triggered, so the text does not update.

Reproducer
A minimal example project has been provided with user-specific signing information removed.

Steps to Reproduce
1. Set up an iOS project using Qt 6.8.0–6.8.3 and Xcode 16.2.

2. Register a handler with QDesktopServices::setUrlHandler.

3. Launch the app through a configured Universal Link.

4. Observe that the handler is not called and the window text remains unchanged.