Fixed mistake

Author: CharlesDuboisSAP

orchestration/src/test/java/com/sap/ai/sdk/orchestration/spring/OrchestrationChatModelTest.java

@@ -152,7 +152,7 @@ void testStreamCompletion() throws IOException {
       assertThat(deltaList.get(1).getResult().getOutput().getContent()).isEqualTo("Sure");
       assertThat(deltaList.get(2).getResult().getOutput().getContent()).isEqualTo("!");
 
-      assertThat(deltaList.get(1).getResult().getMetadata().getFinishReason()).isEqualTo("");
+      assertThat(deltaList.get(0).getResult().getMetadata().getFinishReason()).isEqualTo("");
       assertThat(deltaList.get(1).getResult().getMetadata().getFinishReason()).isEqualTo("");
       assertThat(deltaList.get(2).getResult().getMetadata().getFinishReason()).isEqualTo("stop");