[EventEngine] Extend the `event_engine_dns` experiment (#34485)

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src/core/lib/experiments/experiments.yaml

@@ -112,7 +112,7 @@
 - name: event_engine_dns
   description:
     If set, use EventEngine DNSResolver for client channel resolution
-  expiry: 2023/10/01
+  expiry: 2024/01/08
   owner: yijiem@google.com
   test_tags: ["cancel_ares_query_test", "resolver_component_tests_runner_invoker"]
   allow_in_fuzzing_config: false