Use fadingpopups for when tooltips change geometry. Retain morphingpopups for notifications.

There are a lot of bugs and glitches with using Morphing Popups with tooltips, especially on Wayland. (Several of: https://bugs.kde.org/buglist.cgi?quicksearch=morphing&list_id=2510435)

Disabling Morphing Popups would solve those glitches, but cause tooltip switching to become jumpy and abrupt. This change makes it look smooth even without Morphing Popups.

Morphing Popups is still retained for use with notifications, as it looks good there and I don't think there are any glitches with it like with tooltips.