SharedQmlEngine: Use built-in operator<< for printing QQmlError
This provides even more context with a pretty multi-line format.
Amends 70d356c2
kf.kcmutils: Error loading QML file qrc:/kcm/kcm_flatpak/permissions.qml
kf.kcmutils: qrc:/kcm/kcm_flatpak/permissions.qml:41:9: Type AddEnvironmentVariableDialog unavailable
AddEnvironmentVariableDialog {
^
kf.kcmutils: qrc:/kcm/kcm_flatpak/AddEnvironmentVariableDialog.qml:18:5: Cannot assign to non-existent property "yahaha"
yahaha: model
^