chore(deps): update istio to v1.21.2 #1511

Job	Run time
lint-check	41s
Select Jobs	6s
Schedule (all, registry1, install) / Test	15m 39s
Schedule (all, registry1, upgrade) / Test	19m 11s
Schedule (all, upstream, install) / Test	15m 35s
Schedule (all, upstream, upgrade) / Test	18m 50s
Schedule (istio, registry1, install) / Test	4m 10s
Schedule (istio, upstream, install) / Test	4m 0s
	1h 18m 12s

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