chore: add final decorator

Change-Id: Ia30514646ce3041e4a89b1b77463581c682427d5

Author: 123liuziming

instrumentation/lettuce/lettuce-5.1/testing/src/main/java/io/opentelemetry/instrumentation/lettuce/v5_1/AbstractLettuceClientTest.java

@@ -43,7 +43,7 @@ public abstract class AbstractLettuceClientTest {
 
   protected static class CustomClientResources implements ClientResources {
 
-    private ClientResources delegate;
+    private final ClientResources delegate;
 
     protected CustomClientResources(Builder builder) {
       this.delegate = builder.build();