TCM: fix example in `http.tls.cipher-suites` option

[xuniq]

Product: TCM
Root document: https://www.tarantool.io/en/doc/latest/tooling/tcm/tcm_configuration_reference/#confval-http.tls.cipher-suites
SME: @ oleg-jukovec

Details

See comment: https://gitlab.corp.mail.ru/tarantool/tdb/tarantooldb/-/merge_requests/180#note_44161198