Desktop background image does not resize after restoring previous resolution

Issue Description

Starting with commit 4803e37d, the desktop background image is not resized after restoring the previous desktop resolution.

Steps to Reproduce Issue

1. Set a desktop background image if one is not already set
2. Open Display settings
3. Select a lower resolution like 1024x768
4. Press the Apply button
5. Select "Restore the previous configuration" in the confirmation dialog
6. Notice the desktop background no longer covers the entire desktop

Expected Behavior

I would expect the desktop background to cover the entire desktop after restoring the old resolution.

Additional Information

N/A

Environment & Versions

• OS distribution and version: Arch Linux
• Overall Xfce version: 4.21
• xfdesktop version (git hash if not a release): 8989e927
• thunar version (if issue related to file/launcher icons): 396b83e8
• Windowing system (X11/Wayland): X11
• Compositor and version (if Wayland): N/A
• GTK Theme: Adwaita
• Icon Theme: elementary
• UI Scale Factor: 1x