fix(iOS, Stack v4): hide back button when root screen is replaced with pop animation (#3770)

## Description

Fixes replacing root screen with `pop` animation by hiding back button.
Previously, back button would appear during the animation even though
there was no reason for it to be visible. This is closely related how
we're handling replace with `pop` animation (we're adding previous top
controller and immediately popping it with animation; UIKit "thinks"
that there is a screen to pop to so it displays back button).

Thanks to @satya164 for reporting the issue.

When testing the change I discovered another bug - when replacing
non-root screen, back button title disappears:


https://github.com/user-attachments/assets/7e45f71b-9df6-4a11-847e-75fe43618da0

This might be a native bug, I added a ticket on our internal board to
investigate:
software-mansion/react-native-screens-labs#1053.

## Changes

- add a check for root pop replace and hide back button in
`setPushViewControllers`

## Before & after - visual documentation

| Before | After |
| --- | --- |
| <video
src="https://github.com/user-attachments/assets/0e42e2d7-d71d-4805-b0b0-8ea3fc3b978a"
/> | <video
src="https://github.com/user-attachments/assets/81d1ce5f-b23c-40fa-ab55-05c18e266604"
/> |

## Test plan

Run `Test3770.tsx`.

## Checklist

- [x] Included code example that can be used to test this change.
- [x] For visual changes, included screenshots / GIFs / recordings
documenting the change.
- [ ] Ensured that CI passes

Author: kligarski

apps/src/tests/issue-tests/Test3770.tsx

@@ -0,0 +1,67 @@
+import React from 'react';
+import { NavigationContainer, ParamListBase } from '@react-navigation/native';
+import {
+  NativeStackNavigationProp,
+  createNativeStackNavigator,
+} from '@react-navigation/native-stack';
+import { Button, ScrollView } from 'react-native';
+import LongText from '../../shared/LongText';
+
+type RouteParamList = {
+  Screen1: undefined;
+  Screen2: undefined;
+};
+
+type NavigationProp<ParamList extends ParamListBase> = {
+  navigation: NativeStackNavigationProp<ParamList>;
+};
+
+type StackNavigationProp = NavigationProp<RouteParamList>;
+
+const Stack = createNativeStackNavigator<RouteParamList>();
+
+function Screen1({ navigation }: StackNavigationProp) {
+  return (
+    <ScrollView contentInsetAdjustmentBehavior="automatic">
+      <Button
+        title="Replace with Screen2"
+        onPress={() => navigation.replace('Screen2')}
+      />
+      <LongText />
+    </ScrollView>
+  );
+}
+
+function Screen2({ navigation }: StackNavigationProp) {
+  return (
+    <ScrollView contentInsetAdjustmentBehavior="automatic">
+      <Button
+        title="Replace with Screen1"
+        onPress={() => navigation.replace('Screen1')}
+      />
+      <LongText />
+    </ScrollView>
+  );
+}
+
+export default function App() {
+  return (
+    <NavigationContainer>
+      <Stack.Navigator>
+        <Stack.Screen
+          name="Screen1"
+          component={Screen1}
+          options={{ headerShown: false, animationTypeForReplace: 'pop' }}
+        />
+        <Stack.Screen
+          name="Screen2"
+          component={Screen2}
+          options={{
+            headerLargeTitleEnabled: true,
+            headerTransparent: true,
+          }}
+        />
+      </Stack.Navigator>
+    </NavigationContainer>
+  );
+}

apps/src/tests/issue-tests/index.ts

@@ -182,6 +182,7 @@ export { default as Test3596 } from './Test3596';
 export { default as Test3611 } from './Test3611';
 export { default as Test3617 } from './Test3617';
 export { default as Test3760 } from './Test3760';
+export { default as Test3770 } from './Test3770';
 export { default as TestScreenAnimation } from './TestScreenAnimation';
 // The following test was meant to demo the "go back" gesture using Reanimated
 // but the associated PR in react-navigation is currently put on hold

ios/RNSScreenStack.mm

@@ -735,6 +735,15 @@ - (void)setPushViewControllers:(NSArray<UIViewController *> *)controllers
         // added the last top element to it and perform (animated) pop
         NSMutableArray *newControllers = [NSMutableArray arrayWithArray:controllers];
         [newControllers addObject:previousTop];
+
+#if !TARGET_OS_TV
+        // If we're replacing root screen, there should be no back button.
+        BOOL isRootReplace = _controller.viewControllers.count == 1 && controllers.count == 1;
+        if (isRootReplace) {
+          previousTop.navigationItem.hidesBackButton = YES;
+        }
+#endif // !TARGET_OS_TV
+
         [_controller setViewControllers:newControllers animated:NO];
         [_controller popViewControllerAnimated:YES];
       }