FontChooser: Make font list appear in alphabetical order

Steps to reproduce

1. Clone the GTK repository and build it using Meson.
2. Run the GTK4 demo: ./_build/demos/gtk-demo/gtk4-demo.
3. Navigate to the "Font Rendering" section in the demo.
4. Open the GtkFontDialogButton and observe the font list in the font chooser.

Current behavior

The font list in the font chooser appears unordered. Fonts are displayed in a non-alphabetical order, which makes it harder to locate a specific font family.

Expected outcome

The font list in the font chooser should be displayed in alphabetical order to improve usability and make it easier to find fonts.

Version information

• GTK Version: 4.14.5
• Operating System: Fedora Linux 40
• Build Configuration: Custom build using Meson.

Additional information

• The issue can be reproduced in the gtk4-demo application under the "Font Rendering" section.
• Sorting the font list alphabetically in the font chooser would improve user experience significantly.
• Terminal output does not provide any warnings or errors related to this behavior.
• Screenshot of the current unordered font list