[azsystemevents] Update for release today. (#23585)

sdk/messaging/eventgrid/azsystemevents/CHANGELOG.md

@@ -1,17 +1,11 @@
 # Release History
 
-## 0.4.3 (Unreleased)
+## 0.4.3 (2024-10-14)
 
 ### Features Added
 
 - New field has been added to ACSIncomingCallEventData: OnBehalfOfCallee.
 
-### Breaking Changes
-
-### Bugs Fixed
-
-### Other Changes
-
 ## 0.4.2 (2024-09-19)
 
 ### Features Added