Move construction of ExpectedSignal where it belongs
Summary:
Deduplicate ExpectedSignal creation code by moving it where it
belongs, into proper constructors.
Reviewers: KDE PIM, dvratil
Reviewed By: KDE PIM, dvratil
Subscribers: dvratil, kde-pim
Tags: KDE PIM
Differential Revision: https://phabricator.kde.org/D16555