contractcourt: fix potential panic during startup (#7936) #11333

Job	Run time
RPC and mobile compilation check	2m 15s
cross compilation	14m 25s
lint code	9m 43s
check commits	0s
sample configuration check	40s
Sqlc check	17s
run unit tests (btcd unit-cover)	15m 56s
run unit tests (unit tags="kvdb_etcd")	21m 22s
run unit tests (unit tags="kvdb_postgres")	18m 8s
run unit tests (unit tags="kvdb_sqlite")	16m 24s
run unit tests (btcd unit-race)	47m 30s
check pinned dependencies (google.golang.org/grpc v1.53.0)	4s
check pinned dependencies (github.com/golang/protobuf v1.5.2)	4s
check release notes updated	3s
run ubuntu itests (btcd, backend=btcd)	47m 13s
run ubuntu itests (bitcoind, backend=bitcoind)	58m 22s
run ubuntu itests (bitcoind-notxindex, backend="bitcoind notxindex")	58m 40s
run ubuntu itests (bitcoind-rpcpolling, backend="bitcoind rpcpolling")	59m 28s
run ubuntu itests (bitcoind-etcd, backend=bitcoind dbbackend=etcd)	1h 28m 26s
run ubuntu itests (bitcoind-postgres, backend=bitcoind dbbackend=postgres)	1h 33m 40s
run ubuntu itests (bitcoind-sqlite, backend=bitcoind dbbackend=sqlite)	1h 2m 0s
run ubuntu itests (neutrino, backend=neutrino)	56m 58s
run windows itest	32m 7s
	11h 43m 45s

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