Only emit product origin in deprecation log if present

The elastic product origin may not always be present when deprecation
messages are emitted. This commit changes the log message created for
deprecations to only emit the product origin field if it is not empty.

closes elastic#81757

server/src/main/java/org/elasticsearch/common/logging/DeprecatedMessage.java

@@ -62,10 +62,12 @@ private static ESLogMessage getEsLogMessage(
             .field(KEY_FIELD_NAME, key)
             .field("elasticsearch.event.category", category.name().toLowerCase(Locale.ROOT));
 
-        if (Strings.isNullOrEmpty(xOpaqueId)) {
-            return esLogMessage;
+        if (Strings.isNullOrEmpty(xOpaqueId) == false) {
+            esLogMessage.field(X_OPAQUE_ID_FIELD_NAME, xOpaqueId)
         }
-
-        return esLogMessage.field(X_OPAQUE_ID_FIELD_NAME, xOpaqueId).field(ELASTIC_ORIGIN_FIELD_NAME, productOrigin);
+        if (Strings.isNullOrEmpty(productOrigin) == false) {
+            esLogMessage.field(ELASTIC_ORIGIN_FIELD_NAME, productOrigin);
+        }
+        return esLogMessage;
     }
 }