[rp-reporter]Handle non-XML formats properly

Related-Prod: PRODX-48948
Change-Id: I39dd55b3d3950b12f5f226eab055dcac0ad17e7a
diff --git a/rp_reporter/rp_reporter/report_from_xml.py b/rp_reporter/rp_reporter/report_from_xml.py
index f0a5429..75bc891 100644
--- a/rp_reporter/rp_reporter/report_from_xml.py
+++ b/rp_reporter/rp_reporter/report_from_xml.py
@@ -9,6 +9,7 @@
 import re
 import wget
 import time
+from xml.etree import ElementTree
 
 from reportportal_client import RPClient
 from reportportal_client.helpers import timestamp
@@ -80,8 +81,10 @@
         except urllib.error.HTTPError:
             print("File is absent")
             return
-        if not open(report_path).read().startswith("<xml"):
-            print("File is absent or not in XML format")
+        try:
+            ElementTree.fromstring(open(report_path).read())
+        except ElementTree.ParseError:
+            print("File is not in XML format")
             return
     if pathlib.Path(report_path).exists():
         report_file = report_path