Card: Restrict actions type from arbitrary QObject to T.Action
This is how it should've been this whole time. The only reason to use a generic QObject would be a consistency with ToolBarLayout which can't name T.Action type due to QQuickAction being a private API in C++.
Potentially an ABI breaking change, since it's property type narrowing. But who cares if you abused the Card with weird objects instead of honest Actions. It has been documented as an even more restrictive org::kde::kirigami::Action
type anyway.