fix api_stability

Signed-off-by: Zhenhuan Chen <[email protected]>

Author: dc3671

tests/unittest/api_stability/references/llm.yaml

@@ -18,6 +18,10 @@ methods:
         annotation: Optional[dict]
         default: null
         status: prototype
+      pp_partition:
+        annotation: Optional[List[int]]
+        default: null
+        status: prototype
       # Stats
       iter_stats_max_iterations:
         annotation: Optional[int]