fix: add missing DurableExecutionArn to StopDurableExecution request body

- Extract ARN from URL path and include in body_data before parsing
- StopDurableExecutionRequest to fix "Request body is required" error.

Author: Rares Polenciuc

src/aws_durable_execution_sdk_python_testing/web/handlers.py

@@ -387,14 +387,16 @@ def handle(self, parsed_route: Route, request: HTTPRequest) -> HTTPResponse:
             HTTPResponse: The HTTP response to send to the client
         """
         try:
-            body_data: dict[str, Any] = self._parse_json_body(request)
-            stop_request: StopDurableExecutionRequest = (
-                StopDurableExecutionRequest.from_dict(body_data)
-            )
+            body_data: dict[str, Any] = self._parse_json_body_optional(request)
 
             stop_route = cast(StopDurableExecutionRoute, parsed_route)
             execution_arn: str = stop_route.arn
 
+            body_data["DurableExecutionArn"] = execution_arn
+            stop_request: StopDurableExecutionRequest = (
+                StopDurableExecutionRequest.from_dict(body_data)
+            )
+
             stop_response: StopDurableExecutionResponse = self.executor.stop_execution(
                 execution_arn, stop_request.error
             )