chore: move SnapsExecutionWebView out of Main navigation stack (#10268)

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## **Description**

This PR Fix a bug happening while app is locked. A state mismatch
between the ExecutionService state and the actual WebView would cause
snap calls to fail.

## **Related issues**

Fixes:

## **Manual testing steps**

1. Go to Settings
2. Enable Notifications if its disabled
3. Lock the app.
4. Try to enable/disable notifications again. 

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**


https://github.com/MetaMask/metamask-mobile/assets/44679989/1060c4a7-fdbd-4b5b-ab6b-fdf2def14655

### **After**


https://github.com/MetaMask/metamask-mobile/assets/44679989/3a6f0052-db86-4f91-9a88-1c4369427d6a

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [x] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [x] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

app/components/Nav/App/index.js

@@ -6,7 +6,7 @@ import React, {
   useState,
 } from 'react';
 import { CommonActions, NavigationContainer } from '@react-navigation/native';
-import { Animated, Linking } from 'react-native';
+import { Animated, Linking, View } from 'react-native';
 import { createStackNavigator } from '@react-navigation/stack';
 import Login from '../../Views/Login';
 import QRScanner from '../../Views/QRScanner';
@@ -111,6 +111,9 @@ import DefaultSettings from '../../Views/OnboardingSuccess/DefaultSettings';
 import BasicFunctionalityModal from '../../UI/BasicFunctionality/BasicFunctionalityModal/BasicFunctionalityModal';
 import SmartTransactionsOptInModal from '../../Views/SmartTransactionsOptInModal/SmartTranactionsOptInModal';
 import NFTAutoDetectionModal from '../../../../app/components/Views/NFTAutoDetectionModal/NFTAutoDetectionModal';
+///: BEGIN:ONLY_INCLUDE_IF(preinstalled-snaps,external-snaps)
+import { SnapsExecutionWebView } from '../../../lib/snaps';
+///: END:ONLY_INCLUDE_IF
 
 const clearStackNavigatorOptions = {
   headerShown: false,
@@ -771,6 +774,15 @@ const App = ({ userLoggedIn }) => {
     // do not render unless a route is defined
     (route && (
       <>
+        {
+          ///: BEGIN:ONLY_INCLUDE_IF(preinstalled-snaps,external-snaps)
+        }
+        <View>
+          <SnapsExecutionWebView />
+        </View>
+        {
+          ///: END:ONLY_INCLUDE_IF
+        }
         {isBlockaidFeatureEnabled() && <PPOMView />}
         <NavigationContainer
           // Prevents artifacts when navigating between screens

app/components/Nav/Main/index.js

@@ -81,9 +81,6 @@ import {
   startIncomingTransactionPolling,
   stopIncomingTransactionPolling,
 } from '../../../util/transaction-controller';
-///: BEGIN:ONLY_INCLUDE_IF(preinstalled-snaps,external-snaps)
-import { SnapsExecutionWebView } from '../../../lib/snaps';
-///: END:ONLY_INCLUDE_IF
 
 const Stack = createStackNavigator();
 
@@ -365,15 +362,6 @@ const Main = (props) => {
         ) : (
           renderLoader()
         )}
-        {
-          ///: BEGIN:ONLY_INCLUDE_IF(preinstalled-snaps,external-snaps)
-        }
-        <View>
-          <SnapsExecutionWebView />
-        </View>
-        {
-          ///: END:ONLY_INCLUDE_IF
-        }
         <GlobalAlert />
         <FadeOutOverlay />
         <Notification navigation={props.navigation} />