Remove previous from user state changed

* We are removing the previous user state from the public user state changed state. We will consider adding this in the future.

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSIdentityModel.swift

@@ -123,9 +123,8 @@ class OSIdentityModel: OSModel {
         OneSignalUserDefaults.initShared().saveString(forKey: OS_SNAPSHOT_ONESIGNAL_ID, withValue: newOnesignalId)
         OneSignalUserDefaults.initShared().saveString(forKey: OS_SNAPSHOT_EXTERNAL_ID, withValue: newExternalId)
 
-        let prevUserState = OSUserState(onesignalId: prevOnesignalId, externalId: prevExternalId)
         let curUserState = OSUserState(onesignalId: newOnesignalId, externalId: newExternalId)
-        let changedState = OSUserChangedState(previous: prevUserState, current: curUserState)
+        let changedState = OSUserChangedState(current: curUserState)
 
         OneSignalUserManagerImpl.sharedInstance.userStateChangesObserver.notifyChange(changedState)
     }

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSUserState.swift

@@ -49,20 +49,18 @@ public class OSUserState: NSObject {
 
 @objc
 public class OSUserChangedState: NSObject {
-    @objc public let previous: OSUserState
     @objc public let current: OSUserState
 
     @objc public override var description: String {
-        return "<OSUserState:\nprevious: \(self.previous),\ncurrent: \(self.current)\n>"
+        return "<OSUserState:\ncurrent: \(self.current)\n>"
     }
 
-    init(previous: OSUserState, current: OSUserState) {
-        self.previous = previous
+    init(current: OSUserState) {
         self.current = current
     }
 
     @objc public func jsonRepresentation() -> NSDictionary {
-        return ["previous": previous.jsonRepresentation(), "current": current.jsonRepresentation()]
+        return ["current": current.jsonRepresentation()]
     }
 }