Github: Remove Sync action

[imalcolm1]

Description

The cherry-pick syncs do potentially lead to better git history, but as of now they seem to be causing more trouble than they're worth for the current update workflow.

Type of change

• Github

Platforms tested on

• WPF .NET 8
• WinUI
• MAUI WinUI
• MAUI Android
• MAUI iOS
• MAUI MacCatalyst

Checklist

• Self-review of changes
• All changes work as expected on all affected platforms
• There are no warnings related to changes
• Code is commented and follows .NET conventions and standards
• Codemaid and XAML styler extensions have been run on every changed file
• No unrelated changes have been made to any other code or project files
• Screenshots are correct size and display in description tab (800 x 600 on Windows, MAUI mobile platforms use the MAUI Windows screenshot)