pyside: exclude qtwebengine on arm64 linux

[cho-m]

• Have you followed the guidelines for contributing?
• Have you ensured that your commits follow the commit style guide?
• Have you checked that there aren't other open pull requests for the same formula update/change?
• Have you built your formula locally with HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• Is your test running fine brew test <formula>, where <formula> is the name of the formula you're submitting?
• Does your build pass brew audit --strict <formula> (after doing HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source <formula>)? If this is a new formula, does it pass brew audit --new <formula>?

---

At least until we get a self-hosted runner.

[Copilot]

Pull Request Overview

This PR excludes the qtwebengine and qtwebview dependencies for arm64 Linux builds of PySide, addressing a bottling limitation where these Qt components are not yet available on arm64 Linux architecture.

Key changes:

• Restructured macOS-specific dependencies to use on_sonoma :or_newer instead of the previous on_system approach
• Added architecture-specific dependency handling for Linux, limiting qtwebengine and qtwebview to Intel platforms only
• Updated the test to conditionally import WebEngineCore module based on architecture

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.