[Look and feel KCM] Destroy and recreate GHNS button when palette changes

Authored by broulik on Jan 26 2018, 2:53 PM.

Description

[Look and feel KCM] Destroy and recreate GHNS button when palette changes

BUG: 389351
FIXED-IN: 5.12.0

Differential Revision: https://phabricator.kde.org/D10067