[focuschain/task switcher] Remove special handling for minimized windows

Right now KWin moves minimized windows to the end of the task switcher's ordering. However this is a rather confusing and undocumented behavior that explicitly overrides the user's chosen sort ordering, be it "Recently used" or "Stacking order". This makes it a hidden magic behavior of the type that is at risk of being more annoying than useful.

This commit removes the special handling and lets minimized windows live in the appropriate order in the task switcher rather than always putting them last.

Ever since I moved to Plasma three years ago, this has mildly irritated me and removing the behavior instantly makes the task switcher feel much more natural to use to me.

cc @teams/vdg