server: create an end-to-end test verifying redactability

In many cases we log data that is redacted by the log redaction framework. However it is hard to verify two things:

1) Is a specific string correctly redacted in the production logs that are collected
2) Are there any cases we missed where data that should be redacted sneaks through.

Ideally we would have a test that sets fields we expect to be redacted to well known constants and then searches the logs for those strings. For instance, use the test _REDACT_XXX_ as a user name, table name, column name, index name, database name, locality field, value within a column. Then run the system with a number of different operations and search the redacted logs for this sting. If it appears we missed redacting something.

Jira issue: CRDB-34834