[Bugfix] Remove duplicated config keyword max batch size (#1851)

Signed-off-by: tzhouam <tzhouam@connect.ust.hk>
Signed-off-by: Zhou Taichang <tzhouam@connect.ust.hk>

tests/conftest.py

@@ -843,7 +843,7 @@ def modify_stage_config(
                     'async_chunk': True,
                     'stage_args': {
                         0: {'engine_args.max_model_len': 5800},
-                        1: {'runtime.max_batch_size': 2}
+                        1: {'engine_args.max_num_seqs': 2}
                     }
                 }
         deletes: Dictionary containing configurations to delete.