[Bugfix][Diffusion] Bound diffusion execute RPCs with the DP wave timeout (#7745)

Signed-off-by: ChoHee15 <cc5281@126.com>
Signed-off-by: Gao Han <hgaoaf@connect.ust.hk>
Co-authored-by: Gao Han <hgaoaf@connect.ust.hk>

tests/diffusion/diffusion_kv/test_worker_contract.py

@@ -69,7 +69,7 @@ def make_executor() -> tuple[MultiprocDiffusionExecutor, list[tuple]]:
     executor._ensure_open = lambda: None
     calls: list[tuple] = []
 
-    def collective_rpc(method, *, args, unique_reply_rank, exec_all_ranks):
+    def collective_rpc(method, *, args, unique_reply_rank, exec_all_ranks, timeout=None):
         calls.append((method, args, unique_reply_rank, exec_all_ranks))
         return DiffusionOutput(output=None)