fix: preserve disconnect events in api key middleware (#17253)

python/sglang/test/test_utils.py

@@ -1662,6 +1662,7 @@ def run_and_check_memory_leak(
     disable_overlap,
     chunked_prefill_size,
     assert_has_abort,
+    api_key: Optional[str] = None,
 ):
     other_args = [
         "--chunked-prefill-size",
@@ -1689,6 +1690,7 @@ def run_and_check_memory_leak(
         timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
         other_args=other_args,
         return_stdout_stderr=(stdout, stderr),
+        api_key=api_key,
     )
 
     # Launch a thread to stream the output