Observe content view bounds natively to update sheet height on iOS

Replace the async JS bridge round-trip (onLayout → updateLayout()) with
native KVO observation on the content view's bounds. When React Native's
Yoga layout engine sets the frame, the KVO callback fires synchronously
on the same run loop iteration and calls updateLayout() directly. This
eliminates the timing issues that surfaced after enabling iOS 26 design.

https://claude.ai/code/session_01Rp7ef1h3fKh6fhStcjqLJ5

modules/bottom-sheet/src/BottomSheetNativeComponent.tsx

@@ -126,9 +126,9 @@ export class BottomSheetNativeComponent extends React.Component<
               // a console.log() - just sending the log to the CLI is enough.
               // TODO: Get to the bottom of this and fix it properly! -sfn
               setTimeout(() => this.updateLayout())
-            } else {
-              this.updateLayout()
             }
+            // iOS: content height changes are observed natively via KVO on
+            // the content view's bounds, so no JS bridge round-trip needed.
           }}
         />
       </Portal>