fix: Add missing function to SessionContainer class

Author: KShivendu

supertokens_python/recipe/session/interfaces.py

@@ -441,6 +441,10 @@ async def merge_into_access_token_payload(
     def get_user_id(self, user_context: Optional[Dict[str, Any]] = None) -> str:
         pass
 
+    @abstractmethod
+    def get_tenant_id(self, user_context: Optional[Dict[str, Any]] = None) -> str:
+        pass
+
     @abstractmethod
     def get_access_token_payload(
         self, user_context: Optional[Dict[str, Any]] = None