[expo-notifications][expo-permissions] Move notification permission r…

…equesters to notifications package (#8486)

# Why

Fixes https://github.com/unimodules/react-native-unimodules/issues/136. This is what we wanted to do anyway—move code responsible for permissions to respective modules.

# How

- removed `EXUserNotificationPermissionRequester` as it was left only as a fallback for when `expo-notifications` is not installed. Now that in Expo Client `expo-notifications` will be installed, this class would never be used.
- moved remote notification permission requester from `expo-permissions` to `expo-notifications`, effectively removing support for calling `askAsync(Permissions.NOTIFICATIONS)` from `expo-permission` if `expo-notifications` is not installed
  - while moving I write a way for the requester to receive callbacks about permission being accepted or declined. I used a `UIApplicationDelegate` singleton module to which requesters can register to receive callbacks.
  - since new notification permission requesters now may return `null` inside the permission response I had to either:
    - add support for `NSNull` in `EXPermissionsManager` (it is returned by the user notifications permissions requester)
    - exclude `notifications` and `userFacingNotifications` from being saved to kernel service since we don't scope them even so (thanks @lukmccall for the tip!)
    
    We decided to stick to the second idea.

# Test Plan

- [x] Ran Expo Client on an ExpoClient-less device, fetched and asked for both notification-related permissions.

docs/pages/versions/unversioned/sdk/permissions.md

@@ -24,8 +24,8 @@ The following table shows you which permissions correspond to which packages.
 
 | Permission type             | Packages                                  |
 | --------------------------- | ----------------------------------------- |
-| `NOTIFICATIONS`             | `expo-permissions`                        |
-| `USER_FACING_NOTIFICATIONS` | `expo-permissions`                        |
+| `NOTIFICATIONS`             | `expo-notifications`                      |
+| `USER_FACING_NOTIFICATIONS` | `expo-notifications`                      |
 | `LOCATION`                  | `expo-location`                           |
 | `CAMERA`                    | `expo-camera`, `expo-barcode-scanner`     |
 | `AUDIO_RECORDING`           | `expo-av`                                 |

ios/Exponent/Versioned/Core/UniversalModules/Permissions/EXScopedPermissions.m

@@ -70,7 +70,10 @@ - (void)askForPermissionUsingRequesterClass:(Class)requesterClass
     // ask for permission. If granted then save it as scope permission
     void (^customOnResults)(NSDictionary *) = ^(NSDictionary *permission){
       UM_ENSURE_STRONGIFY(self)
-      [self.permissionsService savePermission:permission ofType:permissionType forExperience:self.experienceId];
+      // if permission should be scoped save it
+      if ([self shouldVerifyScopedPermission:permissionType]) {
+        [self.permissionsService savePermission:permission ofType:permissionType forExperience:self.experienceId];
+      }
       resolve(permission);
     };