[widgets][assetwidget] Clear the JSON preview if current asset it delete

beat/editor/widgets/assetwidget.py

@@ -301,6 +301,7 @@ class AssetWidget(QWidget):
             if answer == QMessageBox.No:
                 return
             self.set_current_editor(AssetType.UNKNOWN)
+            self.json_widget.clear()
             self.__clear_watcher()
 
         path = file_path[len(self.prefix_root_path) + 1 :]