fix task scrub icon list sometimes being off center

also fix animation duration and easing type not being in sync with task preview list

Before merging I'd do some more tests, but so far all seems fine/fixed with this. It's a bit annoying to test the center alignment because it only goes off center with a large amount of tasks (I think when the task list becomes too wide for the screen and that is a hassle when testing on laptop with a 16:9 screen at 100% scaling)

Did an on-device test, all seems good

fixes #392 (closed)