Make user proper of EmbeddingModelConfig optional

Author: geoand

openai/openai-vanilla/runtime/src/main/java/io/quarkiverse/langchain4j/openai/runtime/OpenAiRecorder.java

@@ -103,8 +103,11 @@ public Supplier<?> embeddingModel(Langchain4jOpenAiConfig runtimeConfig) {
                 .maxRetries(runtimeConfig.maxRetries())
                 .logRequests(firstOrDefault(false, embeddingModelConfig.logRequests(), runtimeConfig.logRequests()))
                 .logResponses(firstOrDefault(false, embeddingModelConfig.logResponses(), runtimeConfig.logResponses()))
-                .modelName(embeddingModelConfig.modelName())
-                .user(embeddingModelConfig.user());
+                .modelName(embeddingModelConfig.modelName());
+
+        if (embeddingModelConfig.user().isPresent()) {
+            builder.user(embeddingModelConfig.user().get());
+        }
 
         runtimeConfig.organizationId().ifPresent(builder::organizationId);
 

openai/openai-vanilla/runtime/src/main/java/io/quarkiverse/langchain4j/openai/runtime/config/EmbeddingModelConfig.java

@@ -30,6 +30,5 @@ public interface EmbeddingModelConfig {
     /**
      * A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse.
      */
-    @WithDefault("default")
-    String user();
+    Optional<String> user();
 }