use mdc AttributeKey from captureMdcAttributes

Author: philsttr

instrumentation/log4j/log4j-appender-1.2/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/log4j/appender/v1_2/LogEventMapper.java

@@ -189,7 +189,7 @@ private void captureMdcAttributes(LogRecordBuilder builder) {
 
     for (Map.Entry<String, AttributeKey<String>> entry : captureMdcAttributes.entrySet()) {
       Object value = context.get(entry.getKey());
-      setAttributeOrEventName(builder, getMdcAttributeKey(entry.getKey()), value);
+      setAttributeOrEventName(builder, entry.getValue(), value);
     }
   }