When we show user tips, we immediately send an AJAX request to mark the
tiup as seen. This is done in the background. However, when system tests
are run, sometimes that request is not completed before the test ends.
This causes the test to be flakey.
One way to fix this is to force the system test run to wait for the AJAX
request to complete. However, this is not ideal because it makes the
test suite slower on each run.
Instead, this commit removes the flakey assertion and adds an alternative
assertion in the frontend tests that ensures the background request is
sent when the user tip is shown.
5958ad89f2