Grabbing touch input events is not working.

The attached example demonstrates that grabbing input events via `setExclusiveGrabber` is not working for touch inputs. But for mouse input events, it is working.

Detailed description of the example:
The application implements drag&drop. `DragTile` component contains a `MouseArea` that starts dragging on long pressed mouse event. Than it creates `BaseDragMouseArea` component using `createObject` and delegates data that will be dragged.
`BaseDragMouseArea` contains also a mouse area and sends an artificial mouse event to itself.
`TestEventFilter` receives that event and sets the exclusive grabber via `setExclusiveGrabber`.
At this moment, all events should be delegate to the artificial mouse area and the red/blue rectangles could be dropped into the yellow one.
This is working when I use the mouse but it is not working when use the touch display.
So the exclusive grabber is set (the method is called) but events are not delegated.

With Qt 5.15.x and using `grabMouse` instead of `setExclusiveGrabber` its working like a charm.