Cassandra connector generates invalid schema name for its CDC records

The CDC record generated from cassandra-connector uses schema name with ".Value" suffix and this causes Debezium's ExtractNewRecordState transformer to fail to transform the records. In contrast, other connectors such as mysqsl-connector and postgre-connector generate the valid schema names with ".Envelope" suffix.

Concretely, scenario example-cassandra generates records with schema name "io.debezium.connector.cassandra.test_prefix.testdb.customers.Value". In contrast, scenario example-postgre generates records with schema name "dbserver2.inventory.customers.Envelope". ExtractNewRecordState successfully transform the records from postgre-connector but fails to transform the records from Cassandra-connect as it rejects the records without suffix ".Envelope" at its envelope valiadation step (https://github.com/debezium/debezium/blob/master/debezium-core/src/main/java/io/debezium/transforms/SmtManager.java#L33)