Disallow redundant typecasts. (#15030)

packages/cli/src/ui/hooks/useGeminiStream.ts

@@ -833,10 +833,7 @@ export const useGeminiStream = (
             );
             break;
           case ServerGeminiEventType.Finished:
-            handleFinishedEvent(
-              event as ServerGeminiFinishedEvent,
-              userMessageTimestamp,
-            );
+            handleFinishedEvent(event, userMessageTimestamp);
             break;
           case ServerGeminiEventType.Citation:
             handleCitationEvent(event.value, userMessageTimestamp);