Add support for CREATE USER VALID UNTIL

[ultram4rine]

https://clickhouse.com/docs/sql-reference/statements/create/user#valid-until-clause

❯ clickhouse-sql-parser "CREATE USER test VALID UNTIL '2026-12-12 00:00:00'"
parse statements error: line 0:17 <EOF> or ';' was expected, but got: "VALID"
CREATE USER test VALID UNTIL '2026-12-12 00:00:00'