feat: Build Avalonia editor during CI

[Kryptos-FR]

PR Details

Build the new editor for both Linux and Windows during CI (i.e. merge to xplat-editor).

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My change requires a change to the documentation.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have built and run the editor to try this change out.