Fix dashboards export test (#17768) (#18372)

Test is checking an error message from Kibana that has changed.
(cherry picked from commit 8c9391c)

Co-authored-by: Jaime Soriano Pastor <jsorianopastor@gmail.com>

libbeat/tests/system/test_dashboard.py

@@ -1,12 +1,14 @@
-from base import BaseTest
 import os
 import os.path
+import re
+import requests
+import semver
 import subprocess
-from nose.plugins.attrib import attr
 import unittest
+
+from base import BaseTest
+from nose.plugins.attrib import attr
 from unittest import SkipTest
-import requests
-import semver
 
 INTEGRATION_TESTS = os.environ.get('INTEGRATION_TESTS', False)
 
@@ -188,7 +190,8 @@ def test_export_dashboard_cmd_export_dashboard_by_id_unknown_id(self):
 
         beat.check_wait(exit_code=1)
 
-        assert self.log_contains("error exporting dashboard: Not found") is True
+        expected_error = re.compile("error exporting dashboard:.*not found", re.IGNORECASE)
+        assert self.log_contains(expected_error)
 
     @unittest.skipUnless(INTEGRATION_TESTS, "integration test")
     @attr('integration')