QQuickWindow::tabletEvent() broken in Qt 6.2.1

I first posted about this here on the forums: https://forum.qt.io/topic/131564/qquickwindow-tabletevent-no-longer-works-in-qt6

In a nutshell, I'm trying to port my Qt 5.15.2 app over to Qt 6.2.1.  I'm running on (Ubuntu) Linux w/ GCC and a Wacom tablet.  I sub classed `QQuickWindow` and did an override of `tabletEvent()` to handle, well, Wacom tablet events and then pass them over to QML.  I noticed that it wasn't picking up any tablet events at all.  I've attached a minimal amount of sample code that:

• Creates a `QQuickWindow` subclass which overrides `tabletEvent()`.  Inside of it, there are `qDebug()` statements
• The subclass is registered to QML in the `main()` function.
• In `main.qml`, this window subclass is used as the root window

If you load the project into Qt Creator, and do a Desktop build, one with Qt 5.15.2 and the other with 6.2.1.

You'll notice that 5.x will debug print a lot of messages when using a tablet device over the window (e.g. hover events).  But 6.x will not print any debug messages, which means that `QQuickWindow::tabletEvent()` overrides are broken for this version of Qt.

I understand that the input handling system was changed in Qt, and this might have been a causality, but this is a show stopper for me porting my app to the newer Qt.  I did notice that the supplied tablet example did work, but that doesn't use QML.  The only work around I can think of is to subclass `QQuickWidget` and have that intercept (and dispatch tabtlet events) to QML, but that's a bit of work.