Allow to dismis undo toast

[simmstein]

Describe the bug

Toasts are over the buttons of actions.

To Reproduce

1. Go to a deck
2. Remove a task
3. You must wait several seconds to add a list, to filter tasks, etc.

Screenshots

Expected behavior

Move the toast away from top top right corner.

[juliusknorr]

@skjnldsv @jancborchardt I guess this is more a general issue with the undo approach from #106 so maybe we should also allow to dismis that notification?