Allows rendering a marker symbol below the endpoint of the balloon
callout. Designed to allow balloon callouts to reproduce the same
visual appearance as the older annotation framework items.
The original workaround was only supposed to apply to QList/
QVector of QVariantMaps. By replacing them all in sip we
break mapping of signals defined in c++ which are emitted
by Python code.
Fixes exceptions after running processing algorithms in Qt6
builds.