No need to hydrate identity model twice

* I noticed we were always hydrating the same identity model twice.
* This is because we are parsing a fetch user response, we end up hydrating the identity model twice, unnecessarily, which drives caching it twice as well.
* We already hydrate the identity model attached to the request.
* Here, we were hydrating it again if the current user is the same. However, if the current user is the same, the model is the same and has already been hydrated.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalUser/Source/Executors/OSUserExecutor.swift

@@ -520,10 +520,6 @@ extension OSUserExecutor {
             return
         }
 
-        if let identityObject = parseIdentityObjectResponse(response) {
-            OneSignalUserManagerImpl.sharedInstance.user.identityModel.hydrate(identityObject)
-        }
-
         if let propertiesObject = parsePropertiesObjectResponse(response) {
             OneSignalUserManagerImpl.sharedInstance.user.propertiesModel.hydrate(propertiesObject)
         }