Merge pull request #8368 from edx/benp/flag-flaky-import-export

Flag test as flaky.

common/test/acceptance/tests/studio/test_import_export.py

 """
 Acceptance tests for the Import and Export pages
 """
+from flaky import flaky
+
 from abc import abstractmethod
 from bok_choy.promise import EmptyPromise
 from datetime import datetime
@@ -184,6 +186,7 @@ class ImportTestMixin(object):
         self.import_page.upload_tarball(self.tarball_name)
         self.import_page.wait_for_upload()
 
+    @flaky  # TODO: fix this. See TNL-2386
     def test_import_timestamp(self):
         """
         Scenario: I perform a course / library import