[fix](be) Load JNI log4j2 properties config (#63063)

Problem Summary: ScannerLoader forced log4j2.xml even when the
file-based log4j2.properties resource should be used, causing JNI logs
to keep using the XML configuration.

Author: Gabriel39

fe/be-java-extensions/java-common/src/main/java/org/apache/doris/common/classloader/ScannerLoader.java

@@ -63,7 +63,7 @@ public class ScannerLoader {
             }
 
             // Point log4j2 to our configuration file in classpath
-            System.setProperty("log4j2.configurationFile", "log4j2.xml");
+            System.setProperty("log4j2.configurationFile", "log4j2.properties");
 
             // Disable log4j2's shutdown hook to prevent premature shutdown in JNI environment
             System.setProperty("log4j.shutdownHookEnabled", "false");