(DOCSP-21182): Removed back and restore multi-cluster limitation.

Author: corryroot

source/multi-cluster-arch.txt

@@ -26,7 +26,6 @@ clusters are not available in the beta release of the |multi-clusters|:
 
 - Sharded cluster deployments
 - LDAP authentication
-- Backup and restore
 - X.509 user authentication
 - |onprem| version earlier than 5.0
 - Split Horizon