Reject TwoPC calls if semi-sync is not enabled #757

Job	Run time
Set push variable	1s
Build and push vttestserver (mysql80)	2m 7s
Build and push lite (latest)	2m 27s
Build and push lite (percona80)	2m 19s
Build and push (bullseye, vtadmin)	1m 19s
Build and push (bullseye, vtorc)	28s
Build and push (bullseye, vtgate)	59s
Build and push (bullseye, vttablet)	39s
Build and push (bullseye, mysqlctld)	43s
Build and push (bullseye, mysqlctl)	33s
Build and push (bullseye, vtctl)	39s
Build and push (bullseye, vtctlclient)	43s
Build and push (bullseye, vtctld)	1m 24s
Build and push (bullseye, vtctldclient)	39s
Build and push (bullseye, logrotate)	23s
Build and push (bullseye, logtail)	21s
Build and push (bullseye, vtbackup)	36s
Build and push (bullseye, vtexplain)	33s
Build and push (bookworm, vtadmin)	1m 22s
Build and push (bookworm, vtorc)	39s
Build and push (bookworm, vtgate)	35s
Build and push (bookworm, vttablet)	43s
Build and push (bookworm, mysqlctld)	44s
Build and push (bookworm, mysqlctl)	38s
Build and push (bookworm, vtctl)	39s
Build and push (bookworm, vtctlclient)	37s
Build and push (bookworm, vtctld)	1m 13s
Build and push (bookworm, vtctldclient)	37s
Build and push (bookworm, logrotate)	22s
Build and push (bookworm, logtail)	26s
Build and push (bookworm, vtbackup)	56s
Build and push (bookworm, vtexplain)	39s
	27m 3s

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