This code was trying to filter out the configure action but failing because it was comparing a QMenuItem to a QAction. We need to compare the QMenuItem's internal QAction in order for the configure action to ever match.
Now the overflow menu for System Tray applets no longer shows a redundant configure action:
If this change is accepted, I will push a similar commit to
[plasma-framework]/src/declarativeimports/plasmaextracomponents/qml/BasicPlasmoidHeading.qml as it contains a copy of this logic with the same error.