Do not redefine QWebEngineView::iconChanged.
This fixes the following warning:
QMetaObject::indexOfSignal: signal iconChanged(QIcon) from
QWebEngineView redefined in WebView

Change-Id: I2489bfcf9379200f9bfa24345b56679f138894fe
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>