pytest: fix regex in test_important_plugin

Fix the expected broken-log pattern in test_important_plugin.

Author: vincenzopalazzo

tests/test_plugin.py

@@ -2530,7 +2530,7 @@ def test_important_plugin(node_factory):
     n = node_factory.get_node(options={"important-plugin": os.path.join(pluginsdir, "nonexistent")},
                               may_fail=True, expect_fail=True,
                               # Other plugins can complain as lightningd stops suddenly:
-                              broken_log='Plugin marked as important, shutting down lightningd|Reading sync lightningd: Connection reset by peer|Lost connection to the RPC socket|Plugin terminated before replying to RPC call|plugin-cln-xpay: askrene-create-layer failed with.*Unkown command',
+                              broken_log='Plugin marked as important, shutting down lightningd|Reading sync lightningd: Connection reset by peer|Lost connection to the RPC socket|Plugin terminated before replying to RPC call|plugin-cln-xpay: askrene-create-layer failed with.*Unknown command',
                               start=False)
 
     n.daemon.start(wait_for_initialized=False, stderr_redir=True)