Tidy up linking with KUserFeedback
Obsoletes https://invent.kde.org/libraries/kuserfeedback/-/merge_requests/22 by adding the required includes in KMail, instead. While here, tidy up some of the linking-to-optional-targets.
Obsoletes https://invent.kde.org/libraries/kuserfeedback/-/merge_requests/22 by adding the required includes in KMail, instead. While here, tidy up some of the linking-to-optional-targets.