Fix bug where periodics were being registered multiple times (or, at least twice)

Author: code-monet

gremlin/user_script.py

@@ -535,6 +535,8 @@ def to_xml(self) -> ElementTree.Element:
     def reload(self):
         Script.variable_registry.register_script(self)
         self.module._script_id = self.id
+        # Clear periodic registry to avoid duplicate entries.
+        periodic_registry.clear()
         self.spec.loader.exec_module(self.module)
 
     def _retrieve_variable_definitions(self):