Don't request XDG activation tokens for tasks with StartupNotify=false
Otherwise they get a spinning circle in the task manager. Alternative to plasma/plasma-workspace!2336 (closed).
cc @ngraham @davidedmundson @nicolasfella
Also accounts for X-KDE-StartupNotify.
I'm setting the target branch to kf5, please tell me if this is wrong. This is my first Frameworks MR post-KF6-branching.