deps.qt: Backport upstream patch removing AGL linkage from macOS

[PatTheMav]

Description

Backports the qtbase commit removing AGL from the list of linked frameworks when OpenGL is used by Qt.

Original commit: https://codereview.qt-project.org/c/qt/qtbase/+/652022

Motivation and Context

The AGL framework (the Carbon OpenGL bindings) has been removed in macOS 26. Without this change, it's not possible to build OBS Studio with Xcode 26 and the macOS 26 platform SDK.

How Has This Been Tested?

Tested on macOS 26 (25A5316i) with Xcode 26 beta 4 (17A5285i). Project configured, built, and ran without issue.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.