In RasterImageView events related to AbstractRasterImageViewTool are
propagated to the parent class in case they have not been accepted. In
case a tool derived from AbstractRasterImageViewTool does not
implement its own handler for an event, the empty handler of
AbstractRasterImageViewTool is used. Since "by default isAccepted()
is set to true" according to the QEvent docs, this then results in
events not being propagated.
This can lead to issues, as demonstrated in D14286. As a follow-up to
that and to D14755, let's ignore() events by default in
AbstractRasterImageViewTool, so they are passed on.
Depends on D14485