Fix type annotation on extract_registry_entry_config (#3623)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/util.py

@@ -34,7 +34,7 @@ class RegistryEntry:
         return Schema(self.raw_schema)
 
 
-class Registry(dict):
+class Registry(dict[str, RegistryEntry]):
     def __init__(self, base_schema=None, type_id_key=None):
         super().__init__()
         self.base_schema = base_schema or {}