tapd: fix mutex deadlock in universe cache #3802

Job	Run time
Compilation check	1m 40s
Docker build check	3m 53s
Format check	19s
cross compilation	12m 9s
run itests	12m 10s
run itests postgres	20m 6s
Lint check	2m 50s
migration version check	13s
go mod check	25s
run LiT tests	15m 36s
RPC check	1m 10s
sample configuration check	39s
Sqlc check	2m 50s
test vector check	57s
run unit tests (unit-race)	14m 52s
run unit tests (unit-cover)	4m 22s
run unit tests (unit dbbackend=postgres)	6m 11s
finish	3s
	1h 40m 25s

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