Auto-hide Task a few seconds after marking it as done

## What Happened
When I create a new list, add a task to this list and mark the created task as done it is still shown to me. The `show completed` switch is set to off.

## Expected Behavior
When I create a new list, add a task to this list and mark the created task as done it should not be shown to me, except when I set the `show completed `switch to on before.

## Steps to Reproduce

1. Create a new task list
2. Select the new task list
3. Create a task in the selected task list
4.
## Platform Information
I'm using Elementary OS 6 Beta. I don't know where to look for the version of Tasks, as it is not shown in AppCenter. But I'm guessing I'm using the latest version.