fix: change default value of context of ScreenGestureDetector, add wa…

…rning for goBackGesture (software-mansion#2013)

## Description
Previously, after going from one screen to another (or after opening the
app) there was an error regarding ScreenGestureDetector:

`Warning: Invalid prop 'gestureDetectorBridge' supplied to
'React.Fragment'. React.Fragment can only have 'key' and 'children'
props.`

This error indicates that we were passing props from
ScreenGestureDetector to React.Fragment. Indeed, after looking onto the
default value of GHContext, there was a Fragment that was receiving
invalid props.
This PR fixes this by changing the look of React.Fragment, so we won't
pass the props further.

Also, I've added a warning that is being shown when user tries to use
`goBackGesture` and the navigator is not wrapped in
ScreenGestureDetector.

Fixes software-mansion#2010.

## Changes

- Fix warning of React.Fragment when the ScreenGestureDetector isn't
mounted
- Add warning when user tries to use `goBackGesture` and the navigator
is not wrapped in ScreenGestureDetector
- Reformated code a bit

## Screenshots / GIFs

### Before


https://github.com/software-mansion/react-native-screens/assets/23281839/f3517b73-de80-45a5-847e-bd817d3d2682

### After

Video shows behavior on going from one screen to another and a warning
when there's prop `goBackGesture` without ScreenGestureProvider.


https://github.com/software-mansion/react-native-screens/assets/23281839/7b477ea6-08cc-40ed-afd5-879675776007

## Test code and steps to reproduce

You can test the changes in a several ways:
- By checking Screen animation example from ScreensExample
- By checking Test42 from TestsExample
- By checking TestScreenAnimation from FabricTestExample

## Checklist

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

src/index.native.tsx

@@ -1,11 +1,5 @@
 /* eslint-disable @typescript-eslint/no-var-requires */
-import React, {
-  Fragment,
-  PropsWithChildren,
-  ReactNode,
-  useEffect,
-  useRef,
-} from 'react';
+import React, { PropsWithChildren, ReactNode, useEffect, useRef } from 'react';
 import {
   Animated,
   Image,
@@ -581,7 +575,9 @@ export type {
 const ScreenContext = React.createContext(InnerScreen);
 
 // context to be used when the user wants full screen swipe (see `gesture-handler` folder in repo)
-const GHContext = React.createContext(Fragment);
+const GHContext = React.createContext(
+  (props: { children: React.ReactNode }) => <>{props.children}</>
+);
 
 class Screen extends React.Component<ScreenProps> {
   static contextType = ScreenContext;

src/native-stack/views/NativeStackView.tsx

@@ -419,7 +419,8 @@ function NativeStackViewInner({
   const { key, routes } = state;
 
   const currentRouteKey = routes[state.index].key;
-  const topScreenOptions = descriptors[currentRouteKey].options;
+  const { goBackGesture, transitionAnimation, screenEdgeGesture } =
+    descriptors[currentRouteKey].options;
   const gestureDetectorBridge = React.useRef<GestureDetectorBridge>({
     stackUseEffectCallback: _stackRef => {
       // this method will be override in GestureDetector
@@ -432,12 +433,23 @@ function NativeStackViewInner({
   const screensRefs = React.useRef<RefHolder>({});
   const ScreenGestureDetector = React.useContext(GHContext);
 
+  React.useEffect(() => {
+    if (
+      ScreenGestureDetector.name !== 'GHWrapper' &&
+      goBackGesture !== undefined
+    ) {
+      console.warn(
+        'Cannot detect GestureDetectorProvider in a screen that uses `goBackGesture`. Make sure your navigator is wrapped in GestureDetectorProvider.'
+      );
+    }
+  }, [ScreenGestureDetector.name, goBackGesture]);
+
   return (
     <ScreenGestureDetector
       gestureDetectorBridge={gestureDetectorBridge}
-      goBackGesture={topScreenOptions?.goBackGesture}
-      transitionAnimation={topScreenOptions?.transitionAnimation}
-      screenEdgeGesture={topScreenOptions?.screenEdgeGesture ?? false}
+      goBackGesture={goBackGesture}
+      transitionAnimation={transitionAnimation}
+      screenEdgeGesture={screenEdgeGesture ?? false}
       screensRefs={screensRefs}
       currentRouteKey={currentRouteKey}>
       <ScreenStack