fix(iOS, Tabs+native-stack): allow for bottom, left, right extended layout edges with native stack header non-translucent (#3012)

## Description

Previously, if native-stack's header was non-translucent, stack would
not allow any extended edges, therefore preventing content from
rendering under translucent tab bar controller (this was especially
noticable with iOS 26).

Now, we only prevent from extending layout for top edge, where
UINavigationController has its UINavigationBar.

I tested basic test screens (`SimpleNativeStack`, `TestHeaderTitle`,
`BottomTabsAndStack`, `HeaderOptions`) on iOS 18 and 26 beta 3 and did
not find any problems related to this change - `edgesForExtendedLayout`
applies for system-related navigation bars and views and I don't think
that we used those on any other edges until now - with native bottom
tabs implementation.

Closes
software-mansion/react-native-screens-labs#216.

Moved from
software-mansion/react-native-screens-labs#243.

## Changes

- change `edgesForExtendedLayout` to all apart from top instead of none


## Screenshots / GIFs

| before | after |
| --- | --- |
| <img width="1206" height="2622" alt="edgesForExtendedLayout_before"
src="https://github.com/user-attachments/assets/fe7dd302-30ef-46a1-8e20-d679ae11387a"
/> | <img width="1206" height="2622" alt="edgesForExtendedLayout_after"
src="https://github.com/user-attachments/assets/9ef16617-46ef-4ab1-aa40-3f8dfc83f953"
/> |



## Test code and steps to reproduce

Open Tab4 on iOS 26.

## Checklist

- [x] Included code example that can be used to test this change
- [ ] Ensured that CI passes

Author: kligarski

ios/RNSScreenStackHeaderConfig.mm

@@ -554,7 +554,7 @@ + (void)updateViewController:(UIViewController *)vc
   if (!shouldHide && !config.translucent) {
     // when nav bar is not translucent we change edgesForExtendedLayout to avoid system laying out
     // the screen underneath navigation controllers
-    vc.edgesForExtendedLayout = UIRectEdgeNone;
+    vc.edgesForExtendedLayout = UIRectEdgeAll - UIRectEdgeTop;
   } else {
     // system default is UIRectEdgeAll
     vc.edgesForExtendedLayout = UIRectEdgeAll;