Change the argument of TaskInterface::done() signal
from bool into DoneResult. Make it consistent with
other TaskTree API.
Introduce toDoneResult(bool success) helper.
Change-Id: I7b3041d7c1ed0317c76adbc1fd37448231e85f82
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: hjk <hjk@qt.io>