[Emulator] Delegate to UI thread instead of assert

src/xenia/emulator.cc

@@ -1445,7 +1445,15 @@ X_STATUS Emulator::CompleteLaunch(const std::filesystem::path& path,
                                   const std::string_view module_path) {
   // Making changes to the UI (setting the icon) and executing game config
   // load callbacks which expect to be called from the UI thread.
-  assert_true(display_window_->app_context().IsInUIThread());
+  // If not on UI thread, dispatch to it synchronously.
+  if (!display_window_->app_context().IsInUIThread()) {
+    X_STATUS result = X_STATUS_UNSUCCESSFUL;
+    display_window_->app_context().CallInUIThreadSynchronous(
+        [this, &path, &module_path, &result]() {
+          result = CompleteLaunch(path, module_path);
+        });
+    return result;
+  }
 
   // Setup NullDevices for raw HDD partition accesses
   // Cache/STFC code baked into games tries reading/writing to these