multi: fix `staticcheck` flags #2820

Job	Run time
go mod check	11m 43s
run LiT itests	3m 45s
build and lint code	4m 50s
run unit-test sqlite3 race	9m 2s
RPC compilation check	1m 37s
SQL compilation check	10s
verify that auto-generated documentation is up-to-date	33s
run unit-test postgres race	10m 23s
run LiT unit tests	6m 43s
	48m 46s

Provide feedback