feat: Remove unused member variables (#4489)

Signed-off-by: YuJie Wan <[email protected]>

Author: eeaters

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

@@ -35,8 +35,6 @@
 import org.springframework.ai.chat.client.advisor.observation.AdvisorObservationConvention;
 import org.springframework.ai.chat.client.advisor.observation.AdvisorObservationDocumentation;
 import org.springframework.ai.chat.client.advisor.observation.DefaultAdvisorObservationConvention;
-import org.springframework.ai.template.TemplateRenderer;
-import org.springframework.ai.template.st.StTemplateRenderer;
 import org.springframework.core.OrderComparator;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
@@ -55,8 +53,6 @@ public class DefaultAroundAdvisorChain implements BaseAdvisorChain {
 
 	public static final AdvisorObservationConvention DEFAULT_OBSERVATION_CONVENTION = new DefaultAdvisorObservationConvention();
 
-	private static final TemplateRenderer DEFAULT_TEMPLATE_RENDERER = StTemplateRenderer.builder().build();
-
 	private final List<CallAdvisor> originalCallAdvisors;
 
 	private final List<StreamAdvisor> originalStreamAdvisors;