fix: hardcoded redshift secret name

[raykrishardi]

if you try to create 2 redshift using this component, secrets manager will throw an error since you try to create a secret that already exists (i.e. has the same name)

error

Resource handler returned message: "The operation failed because the secret SecretRedshiftMasterUser already exists. (Service: SecretsManager, Status Code: 400, Request ID: d37aeb09-24a6-4bb9-ace7-e16fb030c378) (SDK Attempt Count: 1)" (RequestToken: 395e1218-e2c7-599c-926f-e030bae3e4fd, HandlerErrorCode: AlreadyExists)