fix(iOS, FormSheet): Add fallback for searching ScrollView which is inside SAV (#3479)

## Description

Fixes a regression in ScrollView with non-scrolling content when using
absolute styles. Adding a SAV into the hierarchy - as a workaround to
content's padding issues under the header on iOS 26 - broke the logic
for finding the ScrollView inside the `ScreenContentWrapper`, preventing
the frame correction from being applied properly. This PR adds fallbacks
to search for the `ScrollView` within the subviews of the
`SafeAreaView`.

> [!NOTE]  
> Allowing the `flex:1` style for the `ContentWrapper` also resolves an
issue with ScrollView's `contentInsetsAdjustmentBehavior`, which now
works correctly with synchronous state updates enabled. It would be good
to align this behavior for the `absoluteWithNoBottom` style as well -
software-mansion/react-native-screens-labs#718

## Changes

- Added fallback logic to search within `SafeAreaView` subviews for
`ScrollView` in `ContentWrapper`.

## Screenshots / GIFs

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### Before

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<video
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    </td>
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<video
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    </td>
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</table>

### After

<table>
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## Test code and steps to reproduce

Tested on TestFormSheet

## Checklist

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

Author: t0maboro

ios/RNSScreen.mm

@@ -30,6 +30,7 @@
 #import <React/RCTUIManagerUtils.h>
 
 #import "RNSConversions.h"
+#import "RNSSafeAreaViewComponentView.h"
 #import "RNSSafeAreaViewNotifications.h"
 #import "RNSScreenFooter.h"
 #import "RNSScreenStack.h"
@@ -902,7 +903,8 @@ - (nullable RNS_REACT_SCROLL_VIEW_COMPONENT *)tryFindDescendantScrollView
   // Step 1: Query registered content wrapper for the scrollview.
   RNSScreenContentWrapper *contentWrapper = _contentWrapperBox.contentWrapper;
 
-  if (RNS_REACT_SCROLL_VIEW_COMPONENT *_Nullable scrollViewComponent = [contentWrapper childRCTScrollViewComponent];
+  if (RNS_REACT_SCROLL_VIEW_COMPONENT *_Nullable scrollViewComponent =
+          [contentWrapper childRCTScrollViewComponentAndContentContainer].scrollViewComponent;
       scrollViewComponent != nil) {
     return scrollViewComponent;
   }
@@ -916,6 +918,20 @@ - (nullable RNS_REACT_SCROLL_VIEW_COMPONENT *)tryFindDescendantScrollView
     }
   }
 
+#if RNS_IPHONE_OS_VERSION_AVAILABLE(26_0)
+  // Fallback 2: Search through RNSSafeAreaViewComponentView subviews (iOS 26+ workaround with modified hierarchy)
+  if (@available(iOS 26.0, *)) {
+    UIView *maybeSafeAreaView = contentWrapper.subviews.firstObject;
+    if ([maybeSafeAreaView isKindOfClass:RNSSafeAreaViewComponentView.class]) {
+      for (UIView *subview in maybeSafeAreaView.subviews) {
+        if ([subview isKindOfClass:RNS_REACT_SCROLL_VIEW_COMPONENT.class]) {
+          return static_cast<RNS_REACT_SCROLL_VIEW_COMPONENT *>(subview);
+        }
+      }
+    }
+  }
+#endif // RNS_IPHONE_OS_VERSION_AVAILABLE(26_0)
+
   return nil;
 }
 

ios/RNSScreenContentWrapper.h

@@ -25,6 +25,11 @@ NS_ASSUME_NONNULL_BEGIN
 
 @end
 
+typedef struct {
+  RNS_REACT_SCROLL_VIEW_COMPONENT *scrollViewComponent;
+  UIView *contentContainerView;
+} RNSScrollViewSearchResult;
+
 @interface RNSScreenContentWrapper :
 #ifdef RCT_NEW_ARCH_ENABLED
     RCTViewComponentView
@@ -39,7 +44,7 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)triggerDelegateUpdate;
 
-- (nullable RNS_REACT_SCROLL_VIEW_COMPONENT *)childRCTScrollViewComponent;
+- (RNSScrollViewSearchResult)childRCTScrollViewComponentAndContentContainer;
 
 - (BOOL)coerceChildScrollViewComponentSizeToSize:(CGSize)size;
 

ios/RNSScreenContentWrapper.mm

@@ -1,5 +1,6 @@
 #import "RNSScreenContentWrapper.h"
 #import "RNSDefines.h"
+#import "RNSSafeAreaViewComponentView.h"
 #import "RNSScreen.h"
 #import "RNSScreenStack.h"
 
@@ -106,32 +107,55 @@ - (nullable RNSScreenView *)findFirstScreenViewAncestor
   return static_cast<RNSScreenView *_Nullable>(currentView);
 }
 
-- (nullable RNS_REACT_SCROLL_VIEW_COMPONENT *)childRCTScrollViewComponent
+- (RNSScrollViewSearchResult)childRCTScrollViewComponentAndContentContainer
 {
+  // Directly search subviews
   for (UIView *subview in self.subviews) {
     if ([subview isKindOfClass:RNS_REACT_SCROLL_VIEW_COMPONENT.class]) {
-      return static_cast<RNS_REACT_SCROLL_VIEW_COMPONENT *>(subview);
+      return (RNSScrollViewSearchResult){.scrollViewComponent = static_cast<RNS_REACT_SCROLL_VIEW_COMPONENT *>(subview),
+                                         .contentContainerView = self};
     }
   }
-  return nil;
+
+  // Fallback 1: Search through RNSSafeAreaViewComponentView subviews (iOS 26+ workaround with modified hierarchy)
+#if RNS_IPHONE_OS_VERSION_AVAILABLE(26_0)
+  if (@available(iOS 26.0, *)) {
+    UIView *maybeSafeAreaView = self.subviews.firstObject;
+    if ([maybeSafeAreaView isKindOfClass:RNSSafeAreaViewComponentView.class]) {
+      for (UIView *subview in maybeSafeAreaView.subviews) {
+        if ([subview isKindOfClass:RNS_REACT_SCROLL_VIEW_COMPONENT.class]) {
+          return (RNSScrollViewSearchResult){
+              .scrollViewComponent = static_cast<RNS_REACT_SCROLL_VIEW_COMPONENT *>(subview),
+              .contentContainerView = maybeSafeAreaView};
+        }
+      }
+    }
+  }
+#endif // RNS_IPHONE_OS_VERSION_AVAILABLE(26_0)
+
+  return (RNSScrollViewSearchResult){.scrollViewComponent = nullptr, .contentContainerView = nullptr};
 }
 
 - (BOOL)coerceChildScrollViewComponentSizeToSize:(CGSize)size
 {
-  RNS_REACT_SCROLL_VIEW_COMPONENT *_Nullable scrollViewComponent = [self childRCTScrollViewComponent];
+  auto scrollViewComponentAndContentContainerPair = [self childRCTScrollViewComponentAndContentContainer];
+  RNS_REACT_SCROLL_VIEW_COMPONENT *_Nullable scrollViewComponent =
+      scrollViewComponentAndContentContainerPair.scrollViewComponent;
+  UIView *_Nullable containerView = scrollViewComponentAndContentContainerPair.contentContainerView;
 
   if (scrollViewComponent == nil) {
     return NO;
   }
 
-  if (self.subviews.count > 2) {
+  if (containerView.subviews.count > 2) {
     RCTLogWarn(
-        @"[RNScreens] FormSheet with ScrollView expects at most 2 subviews. Got %ld. This might result in incorrect layout. \
+        @"[RNScreens] FormSheet with ScrollView expects at most 2 subviews. Got %ld for container: %@. This might result in incorrect layout. \
           If you want to display header alongside the scrollView, make sure to apply `collapsable: false` on your header component view.",
-        self.subviews.count);
+        containerView.subviews.count,
+        NSStringFromClass(containerView.class));
   }
 
-  NSUInteger scrollViewComponentIndex = [[self subviews] indexOfObject:scrollViewComponent];
+  NSUInteger scrollViewComponentIndex = [containerView.subviews indexOfObject:scrollViewComponent];
 
   // Case 1: ScrollView first child - takes whole size.
   if (scrollViewComponentIndex == 0) {
@@ -143,7 +167,7 @@ - (BOOL)coerceChildScrollViewComponentSizeToSize:(CGSize)size
 
   // Case 2: There is a header - we adjust scrollview size by the header height.
   if (scrollViewComponentIndex == 1) {
-    UIView *headerView = self.subviews[0];
+    UIView *headerView = containerView.subviews[0];
     CGRect newFrame = scrollViewComponent.frame;
     newFrame.size = size;
     newFrame.size.height -= headerView.frame.size.height;