ContextualHelpButton: fix translated string usage
Kirigami is a tier-1 framework so we can't use i18n() in code. But we can to so in sample code as lots of other ones do, so let's do that instead.
Kirigami is a tier-1 framework so we can't use i18n() in code. But we can to so in sample code as lots of other ones do, so let's do that instead.