Move properties model's change propagation outside of the lock

* Keep the lock minimal, just around write and read access to the tags dictionary
* Move the events-driving outside of the lock, that create Deltas and caches the model, etc.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSPropertiesModel.swift

@@ -139,19 +139,19 @@ class OSPropertiesModel: OSModel {
             for (key, value) in tags {
                 self.tags[key] = value
             }
-            self.set(property: "tags", newValue: tags)
         }
+        self.set(property: "tags", newValue: tags)
     }
 
     func removeTags(_ tags: [String]) {
+        var tagsToSend: [String: String] = [:]
         tagsLock.withLock {
-            var tagsToSend: [String: String] = [:]
             for tag in tags {
                 self.tags.removeValue(forKey: tag)
                 tagsToSend[tag] = ""
             }
-            self.set(property: "tags", newValue: tagsToSend)
         }
+        self.set(property: "tags", newValue: tagsToSend)
     }
 
     public override func hydrateModel(_ response: [String: Any]) {