fix typo (istio#19255)

Author: zqzzq

samples/multicluster/README.md

@@ -31,7 +31,7 @@ Add clusters to mesh and apply the configuration to build the multicluster
 
 ```bash
 # add clusters to the mesh following the example in the topology file.
-# Clusters are identifed by the context name as defined by the kubeconfig
+# Clusters are identified by the context name as defined by the kubeconfig
 # file.
 ${EDITOR} ${WORKDIR}/topology.yaml