R1:58b55c2fa6d4

Probably improve behavior around duplicate notifications

Summary:
We're sometimes getting duplicate notifications right now. I think this is because multiple windows are racing and becoming leaders.

Clean this up a little:

- Fix the `timeoout` typo.
- Only try to usurp once.
- Use different usurp and expire delays, so we don't fire them at the exact same time.

Not sure if this'll work or not but it should theoretically be a little cleaner.

Test Plan:
- Quit Safari, reopened Safari, still saw a…