remove unused method

Author: markpollack

spring-ai-client-chat/src/main/java/org/springframework/ai/chat/client/DefaultChatClient.java

@@ -522,19 +522,6 @@ private ChatClientResponse doGetObservableChatClientResponse(ChatClientRequest c
 			return chatClientResponse != null ? chatClientResponse : ChatClientResponse.builder().build();
 		}
 
-		@NonNull
-		private static ChatClientRequest augmentPromptWithFormatInstructions(ChatClientRequest chatClientRequest,
-				String outputFormat) {
-			Prompt augmentedPrompt = chatClientRequest.prompt()
-				.augmentUserMessage(userMessage -> userMessage.mutate()
-					.text(userMessage.getText() + System.lineSeparator() + outputFormat)
-					.build());
-			return ChatClientRequest.builder()
-				.prompt(augmentedPrompt)
-				.context(Map.copyOf(chatClientRequest.context()))
-				.build();
-		}
-
 		@Nullable
 		private static String getContentFromChatResponse(@Nullable ChatResponse chatResponse) {
 			return Optional.ofNullable(chatResponse)