Fix panic in vttablet when closing topo server twice (#17094) #396

Job	Run time
Build and push lite (latest)	4m 26s
Build and push vttestserver (mysql80)	2m 32s
Build and push lite (percona80)	4m 31s
Build and push (bullseye, vtadmin)	1m 24s
Build and push (bullseye, vtorc)	39s
Build and push (bullseye, vtgate)	42s
Build and push (bullseye, vttablet)	48s
Build and push (bullseye, mysqlctld)	50s
Build and push (bullseye, mysqlctl)	48s
Build and push (bullseye, vtctl)	55s
Build and push (bullseye, vtctlclient)	54s
Build and push (bullseye, vtctld)	1m 33s
Build and push (bullseye, vtctldclient)	48s
Build and push (bullseye, logrotate)	34s
Build and push (bullseye, logtail)	22s
Build and push (bullseye, vtbackup)	41s
Build and push (bullseye, vtexplain)	52s
Build and push (bookworm, vtadmin)	1m 22s
Build and push (bookworm, vtorc)	2m 32s
Build and push (bookworm, vtgate)	51s
Build and push (bookworm, vttablet)	1m 0s
Build and push (bookworm, mysqlctld)	50s
Build and push (bookworm, mysqlctl)	48s
Build and push (bookworm, vtctl)	43s
Build and push (bookworm, vtctlclient)	45s
Build and push (bookworm, vtctld)	1m 58s
Build and push (bookworm, vtctldclient)	46s
Build and push (bookworm, logrotate)	36s
Build and push (bookworm, logtail)	46s
Build and push (bookworm, vtbackup)	58s
Build and push (bookworm, vtexplain)	53s
Slack Notification if failed	0s
	38m 7s

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