pytest: fix flake in test_onionmessage_ratelimit

Sometimes l1 ratelimits before l2, and l2 receives the warning message, not l1:

```
>       assert l1.daemon.is_in_log('WARNING: Ratelimited onion_message: exceeded one per 250msec')
E       AssertionError: assert None
E        +  where None = <bound method TailableProc.is_in_log of <pyln.testing.utils.LightningD object at 0x7f13435f45b0>>('WARNING: Ratelimited onion_message: exceeded one per 250msec')
E        +    where <bound method TailableProc.is_in_log of <pyln.testing.utils.LightningD object at 0x7f13435f45b0>> = <pyln.testing.utils.LightningD object at 0x7f13435f45b0>.is_in_log
E        +      where <pyln.testing.utils.LightningD object at 0x7f13435f45b0> = <fixtures.LightningNode object at 0x7f13435cbb80>.daemon
...
lightningd-1 2024-11-19T00:45:43.721Z DEBUG   022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59-connectd: peer_in WIRE_ONION_MESSAGE
lightningd-1 2024-11-19T00:45:43.721Z DEBUG   022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59-connectd: peer_out WIRE_WARNING
lightningd-2 2024-11-19T00:45:43.722Z DEBUG   0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-connectd: peer_out WIRE_ONION_MESSAGE
lightningd-2 2024-11-19T00:45:43.722Z DEBUG   connectd: REPLY WIRE_CONNECTD_INJECT_ONIONMSG_REPLY with 0 fds
lightningd-2 2024-11-19T00:45:43.722Z DEBUG   0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-connectd: peer_in WIRE_WARNING
lightningd-2 2024-11-19T00:45:43.722Z INFO    0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-connectd: Received WIRE_WARNING: WARNING: Ratelimited onion_message: exceeded one per 250msec
```

Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

tests/test_pay.py

@@ -5784,7 +5784,9 @@ def test_onionmessage_ratelimit(node_factory):
         for _ in range(8):
             l1.rpc.fetchinvoice(offer['bolt12'])
 
-    assert l1.daemon.is_in_log('WARNING: Ratelimited onion_message: exceeded one per 250msec')
+    # Normally l2 gets upset, but actually l1 can get upset with replies!
+    assert (l1.daemon.is_in_log('WARNING: Ratelimited onion_message: exceeded one per 250msec')
+            or l2.daemon.is_in_log('WARNING: Ratelimited onion_message: exceeded one per 250msec'))
 
     # It will recover though!
     time.sleep(0.250)