[Kernel] - restrict kXNotificationLiveConnectionChanged to startup

- allow for dashboard to show achievements and themes again.

src/xenia/kernel/kernel_state.h

@@ -358,6 +358,7 @@ class KernelState {
   std::unordered_map<uint32_t, XThread*> threads_by_id_;
   std::vector<object_ref<XNotifyListener>> notify_listeners_;
   bool has_notified_startup_ = false;
+  bool has_notified_live_startup_ = false;
 
   object_ref<UserModule> executable_module_;
   std::vector<object_ref<KernelModule>> kernel_modules_;