Fix Java test for new citations field on AssistantMessageEventData

The 1.0.70-0 update added a 'citations' component to the generated
AssistantMessageEvent.AssistantMessageEventData record, so the positional
constructor call in SessionEventHandlingTest needed an extra argument.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 75461183-93f3-4513-a504-4f755211178a

Author: SteveSandersonMS

java/src/test/java/com/github/copilot/SessionEventHandlingTest.java

@@ -865,7 +865,7 @@ private SessionStartEvent createSessionStartEvent(String sessionId) {
     private AssistantMessageEvent createAssistantMessageEvent(String content) {
         var event = new AssistantMessageEvent();
         var data = new AssistantMessageEvent.AssistantMessageEventData(null, null, content, null, null, null, null,
-                null, null, null, null, null, null, null, null, null, null, null);
+                null, null, null, null, null, null, null, null, null, null, null, null);
         event.setData(data);
         return event;
     }