eventcontrollerscroll: Always propagate hold events
Otherwise a stray scroll controller may prevent others from getting hold events, even if it always propagates scroll events and does absolutely nothing.
The specific reason is me trying to support hold gestures in WebKit and not getting them. Turned out MiniBrowser has a second scroll controller to handle ctrl+wheel zooming. Even though it always propagates events when not holding ctrl, the mere fact it exists was enough to break the controller inside WebKitWebView.