Fix onAppear animation issue

[thisIsTheFoxe]

Issue Link 🔗

• View with Navigation Bar side effect #52
• Navigation view animation issue #54

Goals ⚽

We had a bug reappear that we hoped was fixed in f025e9b where the Skeleton loader would fly in from the top left edge of the screen.
From my investigation this and the above mentioned issues are cause inside a NavigationView/Stack when trying to animate a view before it appears on the screen. So the animation tries to animate the view in (starting from the origin).
For more details see this S/O posts:

• SwiftUI: Broken explicit animations in NavigationView?
• Why does an animation in a NavigationView starts from the top left corner?

Implementation Details 🚧

This uses the .task view modifier instead of onAppear when it's available on iOS 15+ and uses the old DispatchQueue logic / fix for previous version. This seems to solve the issue for us.
Also, replacing the implicit .animation modifier with a explicit withAnimation block, see also this Reddit comment:

Implicit only affects the view it is attached to.

This bug seems quite tricky to reproduce reliably tho, and depends on other setup as well. If needed I can look into providing a demo project showcasing the bug. Or alternatively can try to check out FB13795514 on openradar, when it's back up.. :,)

Testing Details 🔍

I got to a state where I could somewhat reliably reproduce the issue and tested it manually many times and as said wasn't able to reproduce the bug with this fix on iOS 18, 26.