[Autotest] Extending timeout in autoupdate.

~60% of AU tests are failing on R80/81. This seeem to be due to the AU
not starting. Of the 40% of tests that pass, nearly all of them take 7-9
seconds to start the AU. Increasing this timeout to 30 will hopefully
help allow the other 60% a bit more time to start.

BUG=None
Test=None

Change-Id: I999c65893de5eab98fc678a8561bfdaa13e799bc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1962816
Tested-by: Derek Beckett <dbeckett@chromium.org>
Reviewed-by: Katherine Threlkeld <kathrelkeld@chromium.org>
Commit-Queue: Derek Beckett <dbeckett@chromium.org>
diff --git a/client/cros/enterprise/enterprise_au_context.py b/client/cros/enterprise/enterprise_au_context.py
index 099a629..c4ecfa9 100644
--- a/client/cros/enterprise/enterprise_au_context.py
+++ b/client/cros/enterprise/enterprise_au_context.py
@@ -74,6 +74,7 @@
 
         utils.poll_for_condition(
                 update_started,
+                timeout=30,
                 exception=error.TestFail('Update did not start!'))