examples: Update lease to export metrics #410

Job	Run time
cleanup	3s
all-check (1.65)	1m 38s
feature-check (admin)	1m 9s
all-check (1.73)	2m 48s
feature-check (admin,prometheus-client)	1m 10s
feature-check (client)	1m 6s
feature-check (client rustls-tls)	32s
feature-check (client openssl-tls)	33s
feature-check (client openssl-tls rustls-tls)	35s
feature-check (errors)	1m 7s
feature-check (index)	1m 7s
feature-check (initialized)	1m 6s
feature-check (lease)	1m 5s
feature-check (log)	1m 5s
feature-check (prometheus-client)	1m 2s
feature-check (requeue)	1m 3s
feature-check (runtime)	1m 7s
feature-check (server)	1m 3s
feature-check (server rustls-tls)	33s
feature-check (server openssl-tls)	33s
feature-check (server openssl-tls rustls-tls)	37s
feature-check (shutdown)	1m 6s
	22m 8s

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