optedIn and enabled will consider provisional as true

* Provisional permission means notifications can be displayed.
* In this case, even though the user has not explicitly accepted push notification permissions, we will consider `optedIn` and `enabled` as true
* In addition, the server also considers this user to be subscribed with provisional permission
* Update the `_accepted` property on a push subscription model to reflect `reachable` instead of `accepted`

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalNotifications/OSPermission.m

@@ -237,7 +237,7 @@ + (void)fireChangesObserver:(OSPermissionStateInternal*)state  {
     // Update the push subscription's _accepted property
     // TODO: This can be called before the User Manager has set itself as the delegate
     if (OSNotificationsManager.delegate && [OSNotificationsManager.delegate respondsToSelector:@selector(setAccepted:)]) {
-        [OSNotificationsManager.delegate setAccepted:state.accepted];
+        [OSNotificationsManager.delegate setAccepted:state.reachable];
     }
 }
 

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSSubscriptionModel.swift

@@ -162,9 +162,13 @@ class OSSubscriptionModel: OSModel {
             self.set(property: "notificationTypes", newValue: notificationTypes)
         }
     }
+
     // swiftlint:disable identifier_name
-    // This is set by the permission state changing
-    // Defaults to true for email & SMS, defaults to false for push
+    /**
+     This is set by the permission state changing.
+     Defaults to true for email & SMS, defaults to false for push.
+     Note that this property reflects the `reachable` property of a permission state. As provisional permission is considered to be `optedIn` and `enabled`.
+     */
     var _accepted: Bool {
         didSet {
             guard self.type == .push && _accepted != oldValue else {