Update notification endpoint (#5177)

Update the endpoint used for in-IDE notifications to the combined startup & emergency 2.x.json schema format.

Author: samgst-amazon

plugins/core/jetbrains-community/resources/META-INF/aws.toolkit.core.xml

@@ -79,7 +79,7 @@
         <registryKey key="aws.toolkit.developerMode" description="Enables features to facilitate development of the toolkit" restartRequired="false"
                      defaultValue="false"/>
         <registryKey key="aws.toolkit.notification.endpoint" description="Endpoint for AWS Toolkit notifications"
-                     defaultValue="https://idetoolkits-hostedfiles.amazonaws.com/Notifications/Jetbrains/emergency/1.x.json" restartRequired="true"/>
+                     defaultValue="https://idetoolkits-hostedfiles.amazonaws.com/Notifications/Jetbrains/combined/2.x.json" restartRequired="true"/>
 
 
         <notificationGroup id="aws.plugin.version.mismatch" displayType="STICKY_BALLOON" key="aws.settings.title"/>