fix(iOS): use prefersPageSizing for modal on iOS 18.0+ (#2797)

## Description

Brings back `stackPresentation: 'modal'`'s size on iOS 18.0+.

Since the release of iOS 18, screens with `stackPresentation: 'modal'`
changed size on devices with a bigger screen, such as an iPad - they
became much smaller, which impacted applications of the library's users
(see issue
#2549).
This happens because `UIModalPresentationAutomatic`, which is used by
`react-native-screens` for modal on iOS, has been changed with the
release of iOS 18. `UIModalPresentationAutomatic` is now mapped to
`UIModalPresentationFormSheet` for iOS >=18 and
`UIModalPresentationPageSheet` for earlier versions (this was the
default before).

For more context please see PR
#2793 but
the TL;DR is that we consider this a breaking change for our users and
therefore we decided to bring back the old behavior for
`react-native-screens` v4 using
[`prefersPageSizing`](https://developer.apple.com/documentation/uikit/uisheetpresentationcontroller/preferspagesizing?language=objc)
property of the `UISheetPresentationController` which has been available
since iOS 17.0+.

Resolves
#2549.

## Changes

- use `prefersPageSizing` for modal on iOS 18.0+

## Screenshots / GIFs

### Before
![Modal without `prefersPageSizing` on iOS
18](https://github.com/user-attachments/assets/724bd109-b0c0-47e4-b897-43cd53ef3dd9)

### After
![Modal with `prefersPageSizing` on iOS
18](https://github.com/user-attachments/assets/b0925934-25dc-4103-8422-8fb07a18fd18)

## Test code and steps to reproduce

Open `Modals` example screen and use `Open modal` button.

## Checklist

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

---------

Co-authored-by: Kacper Kafara <[email protected]>

Author: kligarski

guides/GUIDE_FOR_LIBRARY_AUTHORS.md

@@ -247,7 +247,10 @@ Using `containedModal` and `containedTransparentModal` with other types of modal
 
 For iOS:
 
-- `modal` will use [`UIModalPresentationAutomatic`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationautomatic?language=objc) on iOS 13 and later, and will use [`UIModalPresentationFullScreen`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationfullscreen?language=objc) on iOS 12 and earlier.
+- `modal` will use:
+   *  on iOS 18 and later [`UIModalPresentationAutomatic`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationautomatic?language=objc). However, since the iOS 18 changed the default behaviour from `UIModalPresentationPageSheet` to `UIModalPresentationFormSheet` (it looks vastly different on regular size classes devices, e.g. iPad), for the sake of backward compatibility, we keep the default behaviour from before iOS 18. *This might change in future major release of `react-native-screens`.
+   *  on iOS 13 and later [`UIModalPresentationAutomatic`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationautomatic?language=objc)
+   * on iOS 12 and earlier will use [`UIModalPresentationFullScreen`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationfullscreen?language=objc). 
 - `fullScreenModal` will use [`UIModalPresentationFullScreen`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationfullscreen?language=objc)
 - `formSheet` will use [`UIModalPresentationFormSheet`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationformsheet?language=objc)
 - `transparentModal` will use [`UIModalPresentationOverFullScreen`](https://developer.apple.com/documentation/uikit/uimodalpresentationstyle/uimodalpresentationoverfullscreen?language=objc)

ios/RNSScreen.mm

@@ -246,6 +246,18 @@ - (void)setStackPresentation:(RNSScreenStackPresentation)stackPresentation
       }
 #else
       _controller.modalPresentationStyle = UIModalPresentationFullScreen;
+#endif
+#if defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && defined(__IPHONE_17_0) && \
+    __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_17_0 && !TARGET_OS_TV
+      if (@available(iOS 18.0, *)) {
+        UISheetPresentationController *sheetController = _controller.sheetPresentationController;
+        if (sheetController != nil) {
+          sheetController.prefersPageSizing = true;
+        } else {
+          RCTLogError(
+              @"[RNScreens] sheetPresentationController is null when attempting to set prefersPageSizing for modal");
+        }
+      }
 #endif
       break;
     case RNSScreenStackPresentationFullScreenModal: