kdeconfig: add support for kwriteconfig6 (#10751)
* kdeconfig: add support for kwriteconfig6
Rationale:
With a minimal install of KDE Plasma 6, the kdeconfig module would systematically fail with the following error: `kwriteconfig is not installed.`
In this configuration, kwriteconfig6 is the only version of kwriteconfig installed, and the kdeconfig module did not not find it.
Fixes#10746
* Add changelog fragment
* Update changelogs/fragments/10751-kdeconfig-support-kwriteconfig6.yml
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(cherry picked from commit d6ad9beb58)
Co-authored-by: Thibault Geoffroy <33561374+nebularnoise@users.noreply.github.com>
Co-authored-by: Felix Fontein <felix@fontein.de>
