Review fixes for openai-java-1.1:openai3-testing (open-telemetry#17565)

Author: otelbot[bot]

instrumentation/openai/openai-java-1.1/openai3-testing/src/main/java/io/opentelemetry/instrumentation/openai/v3_0/OpenAi3TestHelper.java

@@ -33,7 +33,7 @@ public ChatCompletionTool chatCompletionTool(FunctionDefinition functionDefiniti
   @Override
   public MessageToolCallBuilder messageToolCallBuilder() {
     return new MessageToolCallBuilder() {
-      final ChatCompletionMessageFunctionToolCall.Builder builder =
+      private final ChatCompletionMessageFunctionToolCall.Builder builder =
           ChatCompletionMessageFunctionToolCall.builder();
 
       @Override
@@ -61,7 +61,7 @@ public FunctionBuilder messageToolCallFunctionBuilder() {
   }
 
   private static class FunctionBuilderImpl implements FunctionBuilder {
-    final ChatCompletionMessageFunctionToolCall.Function.Builder builder =
+    private final ChatCompletionMessageFunctionToolCall.Function.Builder builder =
         ChatCompletionMessageFunctionToolCall.Function.builder();
 
     @Override