Fix iOS11 safeArea effects on scrollView

[gran33]

Issue Description

There is a margin under the top bar that shouldn't be there.
Related to iOS11 and react-native issue:
facebook/react-native#15681

Steps to Reproduce / Code Snippets / Screenshots

Running any app with screen contains any scroll view, when push then pop, the back screen comes from the bottom.

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Environment

• React Native Navigation version: 1.1.85
• React Native version: 0.45.1
• Platform(s) (iOS, Android, or both?): iOS
• Device info (Simulator/Device? OS version? Debug/Release?): Simulator + real device

[gran33]

fixed in #1859

[DanielZlotin]

implement in v2

[gameboyVito]

it's not working on iOS10 while building with Xcode9, though it works on iOS11. See this: facebook/react-native#15957

[gameboyVito]

@gran33 @DanielZlotin
Fixed, I will send you a PR if you don't mind.
Please check #1896

[DanielZlotin]

So the current solution is a bug. This forces the users to specify magic numbers in their code, instead of letting the system do it's thing.

[LeoNatan]

Fixed in v2. Will back-port to v1.