Update wallpaper_cache only when theming is requested

[hurlbutt]

Description

Updates ml4w-wallpaper script to update wallpaper_cache only when --skip-theming is not set.

Changes

• Updates ml4w-wallpaper script to update wallpaper_cache only when --skip-theming is not set.

Context

Right now wallpaper_cache is used for theming purposes. In the event that ml4w-wallpaper is called with the --skip-theming flag set, the related theming aspects are not updated, but the cache file is. The next time the user logs into Hyprland, the autostart logic calls ml4w-wallpaper using normal theming logic. This causes the theming to update itself based on the cached file (which was explicitly marked as not to be used for theming) which is not intended.

This change moves the updating of the cache file to be inside the check for whether to re-theme, and only does so if --skip-theming was not set.

How Has This Been Tested?

Tested by running the script with and without the --skip-theming flag, and verified the contents of wallpaper_cache were as intended. Also tried to set the wallpaper using the --skip-theming flag, restarting Hyprland, and verifying that the theming was not changed from the new wallpaper file.

• Tested on Arch Linux/Based Distro.
• Tested on Fedora Linux/Based Distro.
• Tested on openSuse.

Checklist

Please ensure your pull request meets the following requirements:

• My code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• My changes do not introduce new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes.