Add create_date to our index usage statistics telmetry

We [added a create_date to crdb_internal.table_indexes](https://github.com/cockroachdb/cockroach/issues/72626). We should capture this piece of information in our telemetry channel as well for index usage statistics.

Related PR that added index usage statistics: https://github.com/cockroachdb/cockroach/issues/72486

Jira issue: CRDB-17669