cdc: enable beforeAfterValidator in randomized tests

[rharding6373]

The beforeAfterValidator is an important validator for changefeeds because it tests that emitted messages match the contents of the original tables at their mvcc timestamp. However, the validator today supports only limited data types, since it currently determines whether a row existed or not by creating a SQL query filtered on all fields in the emitted message, but does so inaccurately for some types (e.g., arrays, geo types). Therefore it doesn't work out of the box for randomized testing, which produces tables with all valid database types.

Jira issue: CRDB-43943

[blathers-crl]

cc @cockroachdb/cdc

[wenyihu6]

Closed by #136003.