fix(router): fix tls_passthrough in expression flavor #27631

Job	Run time
build / Build dependencies	14s
DB-less integration tests	15m 39s
Lint, Doc and Unit tests	5m 3s
PDK tests	4m 15s
Postgres integration - first (01-04) tests	18m 55s
Postgres integration - second (>= 05) tests	23m 24s
Postgres plugins - first (01-04) tests	8m 28s
Postgres plugins - second (>= 05) tests	13m 20s
Luacov stats aggregator	0s
	1h 29m 18s

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