[device/ruijie] Mitigation for security vulnerability sonic-net#11779

Signed-off-by: maipbui [email protected]
Why I did it
The xml.etree.ElementTree module is not secure against maliciously constructed data.
How I did it
Remove xml. Use lxml XML parsers package that prevent potentially malicious operation.

Author: maipbui

device/ruijie/x86_64-ruijie_b6510-48vs8cq-r0/monitor.py

@@ -6,8 +6,8 @@
 * PSU
 """
 import os
-import xml.etree.ElementTree as ET
 import glob
+from lxml import etree as ET
 
 MAILBOX_DIR = "/sys/bus/i2c/devices/"
 PORTS_DIR = "/sys/class/net/"