fix: failed to generate spring.ai.tools.observations metadata (#3539)

Signed-off-by: Jionghui Zheng <9uanhuo@gmail.com>
(cherry picked from commit aada198b46)

auto-configurations/models/tool/spring-ai-autoconfigure-model-tool/src/main/java/org/springframework/ai/model/tool/autoconfigure/ToolCallingProperties.java

@@ -31,6 +31,10 @@ public class ToolCallingProperties {
 
 	private final Observations observations = new Observations();
 
+	public Observations getObservations() {
+		return this.observations;
+	}
+
 	/**
 	 * If true, tool calling errors are thrown as exceptions for the caller to handle. If
 	 * false, errors are converted to messages and sent back to the AI model, allowing it