replace user data with the fetch user response

* Motivation: Previously, when we hydrate after fetch user, we are adding to and updating our models, but not doing any removals if local properties are not in the response.
* Instead, replace the user's data with the response, but keep the same identity and property model since it is the same user.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSIdentityModel.swift

@@ -65,6 +65,13 @@ class OSIdentityModel: OSModel {
         self.aliases = aliases
     }
 
+    /**
+     Called to clear the model's data in preparation for hydration via a fetch user call.
+     */
+    func clearData() {
+        self.aliases = [:]
+    }
+
     // MARK: - Alias Methods
 
     func addAliases(_ aliases: [String: String]) {

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSPropertiesModel.swift

@@ -92,6 +92,14 @@ class OSPropertiesModel: OSModel {
         // ... and more
     }
 
+    /**
+     Called to clear the model's data in preparation for hydration via a fetch user call.
+     */
+    func clearData() {
+        // TODO: What about language, lat, long?
+        self.tags = [:]
+    }
+
     // MARK: - Tag Methods
 
     func addTags(_ tags: [String: String]) {

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSUserRequests.swift

@@ -269,6 +269,9 @@ class OSUserExecutor {
         }
 
         OneSignalClient.shared().execute(request) { response in
+            // Clear local data in preparation for hydration
+            OneSignalUserManagerImpl.sharedInstance.clearUserData()
+
             if let response = response {
                 parseFetchUserResponse(response: response, identityModel: request.identityModel, originalPushToken: OneSignalUserManagerImpl.sharedInstance.token)
             }

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OneSignalUserManagerImpl.swift

@@ -283,6 +283,18 @@ public class OneSignalUserManagerImpl: NSObject, OneSignalUserManager {
         )
     }
 
+    /**
+     Clears the existing user's data in preparation for hydration via a fetch user call.
+     */
+    func clearUserData() {
+        // Identity and property models should still be the same instances, but with data cleared
+        _user?.identityModel.clearData()
+        _user?.propertiesModel.clearData()
+
+        // Subscription model store should be cleared completely
+        OneSignalUserManagerImpl.sharedInstance.subscriptionModelStore.clearModelsFromStore()
+    }
+
     private func _login(externalId: String?, token: String?) -> OSUserInternal {
         guard !OneSignalConfigManager.shouldAwaitAppIdAndLogMissingPrivacyConsent(forMethod: nil) else {
             return _mockUser