fix: reduce kde image size #378

Job	Run time
image (x86_64, base/base-disk)	17m 16s
live-iso (x86_64, flagship/flagship-live)	20m 43s
image (x86_64, flagship/base-disk)	31m 7s
live-iso (x86_64, gnome/gnome-live)	1m 53s
image (x86_64, gnome/base-disk)	2m 2s
live-iso (x86_64, kde/kde-live)	33m 39s
image (x86_64, kde/base-disk)	34m 59s
live-iso (x86_64, xfce/xfce-live)	21m 30s
image (x86_64, xfce/base-disk)	31m 7s
live-iso (aarch64, flagship/flagship-live)	1h 40m 44s
image (aarch64, base/base-disk)	20m 33s
live-iso (aarch64, gnome/gnome-live)	9m 37s
image (aarch64, flagship/base-disk)	33m 16s
live-iso (aarch64, kde/kde-live)	1h 29m 26s
image (aarch64, gnome/base-disk)	4m 12s
live-iso (aarch64, xfce/xfce-live)	1h 28m 39s
image (aarch64, kde/base-disk)	20m 35s
image (aarch64, xfce/base-disk)	1h 35m 43s
push-image	0s
	10h 57m 1s

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