Desktop applets are supposed to use the exact same background effects
as popups, not only blurring, but altering the brightness, contrast
and saturation of the wallpaper wit hthe same parameters the kwin
effect is using

CCBUG:473289

Depends from libplasma!1216


before:

![Screenshot_20241031_115918](/uploads/18cd3bb242e4d9df69a6974e1f51de48/Screenshot_20241031_115918.png)

after:

![Screenshot_20241031_115446](/uploads/78f451053761e9406ee0f67853502681/Screenshot_20241031_115446.png)