Fixed nearest font matching not working

[adirh3]

What does the pull request do?

Fixes issue that sometimes font match won't fallback to nearest font when needed, causing it to use the default font

What is the current behavior?

Many fonts are not showing properly on startup (mainly Chinese fonts)

What is the updated/expected behavior with this PR?

All fonts showing properly

How was the solution implemented (if it's not obvious)?

Checklist

• [ ] Added unit tests (if possible)?
• [ ] Added XML documentation to any related classes?
• [ ] Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues