Device mode not supported.md

Add note that device mode destinations are not supported as clients still ask this even if it says only cloud mode are

Author: estgc

src/unify/linked-profiles/linked-events.md

@@ -190,7 +190,7 @@ Segment currently syncs once every hour.
 
 #### Which Destinations does Linked Events support? 
 
-For Linked Events, Segment supports all actions-based destinations in cloud-mode. 
+For Linked Events, Segment supports all actions-based destinations in cloud-mode. Device-mode destinations are not supported.
 
 #### Why aren't test events working?