Don't use view controller appearance methods for managing notification subscription

[odnoletkov]

1. UIKit doesn't guarantee specific order or paring for viewDidAppear and viewDidDisappear (as well as for most other appearance methods combinations). So they can't be used for proper management of the notification lifecycle and can cause over- or under-subscription problems in practice.
2. Why the safe area update shouldn't happen when view is 'disappeared' in the first place?

[a2]

This is great feedback! Thanks so much, @odnoletkov, for pointing it out. I'd gladly accept a PR that fixes this issue. Is that something you could provide? I might be able to do it myself but no guarantees on timeframe since I'm working this week :)