Component: The Snackbar auto-dismissal timeout is reset on every rerender

[Mamaduka]

Currently, the Snackbar auto-dismissal timeout is reset on every rerender. The timers are reset when a notice is added or removed from the SnackbarList. This causes them to be visible a lot longer than expected.

Why

The onRemove callback has a new reference on each rerender, triggers side-effect cleanup, and resets timers.

Possible Solution

Omit onDismiss and onRemove from the side-effect dependencies.

• I think it is safe to assume that the onDismiss callback snapshot won't change after the action is dispatched.
• We can't memoize the curried onRemove function. It will always return a new function.

Step-by-step reproduction instructions

1. Open a post or page.
2. Insert a block.
3. Trigger a few snackbar notices. Copying a block can do that.

Expected behavior

Let's assume there is a one-second difference between message triggers.

Message 1 - 10s
Message 2 - 10s + 1s
Message 3 - 10s + 2s

Current behavior

Message 1 - 10s
Message 2 - 20s (10s after first message)
Message 3 - 30s (10s after second message)

cc @WordPress/gutenberg-components