Add note: File Access Logs (FAL) not supported for cache volumes

JIRA: NFSAAS-153790
Adds a note in the considerations section of configure-cache-volumes.md
informing users that FAL for cache volumes is not yet supported and that
enabling diagnostic settings on a cache volume for FAL has no effect.

Author: netapp-manishc

articles/azure-netapp-files/configure-cache-volumes.md

@@ -65,6 +65,9 @@ If you're enabling write-back on the external origin volume:
 
 You can't use cache volumes if the following features are configured on the source or destination: 
 
+>[!NOTE]
+> File Access Logs (FAL) for cache volumes isn't currently supported. Although diagnostic settings might be available for cache volumes, enabling diagnostic settings on a cache volume to configure File Access Logs has no effect.
+
 #### Unsupported features
 
 The following features can't be used with Azure NetApp Files cache volumes: