Fix flaky mysqlctl blackbox test (#17387) #505

Job	Run time
Build and push vttestserver (mysql80)	2m 37s
Build and push lite (latest)	4m 27s
Build and push lite (percona80)	4m 32s
Build and push (bullseye, vtadmin)	1m 26s
Build and push (bullseye, vtorc)	50s
Build and push (bullseye, vtgate)	52s
Build and push (bullseye, vttablet)	56s
Build and push (bullseye, mysqlctld)	46s
Build and push (bullseye, mysqlctl)	45s
Build and push (bullseye, vtctl)	50s
Build and push (bullseye, vtctlclient)	50s
Build and push (bullseye, vtctld)	1m 39s
Build and push (bullseye, vtctldclient)	48s
Build and push (bullseye, logrotate)	21s
Build and push (bullseye, logtail)	28s
Build and push (bullseye, vtbackup)	51s
Build and push (bullseye, vtexplain)	45s
Build and push (bookworm, vtadmin)	1m 27s
Build and push (bookworm, vtorc)	49s
Build and push (bookworm, vtgate)	59s
Build and push (bookworm, vttablet)	51s
Build and push (bookworm, mysqlctld)	48s
Build and push (bookworm, mysqlctl)	48s
Build and push (bookworm, vtctl)	59s
Build and push (bookworm, vtctlclient)	54s
Build and push (bookworm, vtctld)	1m 37s
Build and push (bookworm, vtctldclient)	59s
Build and push (bookworm, logrotate)	36s
Build and push (bookworm, logtail)	41s
Build and push (bookworm, vtbackup)	52s
Build and push (bookworm, vtexplain)	50s
Slack Notification if failed	0s
	36m 53s

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