ari: Provide the caller ID RDNIS for the channels

Provide the caller ID RDNIS when available. This will allow an
application to follow the redirect.

res/ari/ari_model_validators.h

@@ -1346,6 +1346,7 @@ ari_validator ast_ari_validate_application_fn(void);
  * Channel
  * - accountcode: string (required)
  * - caller: CallerID (required)
+ * - caller_rdnis: string
  * - channelvars: object
  * - connected: CallerID (required)
  * - creationtime: Date (required)