Update Event Tester page

- Update title to match Segment UI 
- Add info section at top of the page to let customers know the Event Tester is only available for server-side integrations

Author: sarahrudy

src/connections/test-connections.md

@@ -1,10 +1,13 @@
 ---
-title: "Testing Connections"
+title: "Event Tester"
 ---
 
 
 Segment has an Event Tester that enables you to test your connections between Segment and your destination. You can access the Event Tester from your Source Debugger, or from your destination settings.   
 
+> info "Available for server-side event streaming destinations only"
+> This feature is only available for server-side integrations (also known as cloud-mode destinations). You will not be able to use this for client-side integrations (also known as device-mode destinations). To use this feature, choose a server-side integration. 
+
 ## Use Cases
 
 There are two scenarios where you might want to use the Event Tester: