For users of this kpart, a read-only property has been introduced to
enable clients to determine the status of the setting in the profile.

Instantiate a konsole part with

KService::Ptr service = KService::serviceByDesktopName(QStringLiteral("konsolepart"));
if( service )
{
    factory = KPluginLoader(service->library()).factory();
}

m_part = factory ? (factory->create<KParts::Part>(parent)) : 0;

and query the property with m_part->property("startInCurrentSessionDir");. It should return the preferences property as set in konsole.