In 245357c868 we added a redirect
after stream creation, to go to the stream feed. This means
the stream settings modal was closed partway through the tests.
This caused a flake where when the modal was reopened it was
not always open by the time we fetched the stream name.
The main fix in this commit is changing the classname for
the stream in the modal to be more specific (`stream-name`
can also be found in the left sidebar in many places) and
waiting for it to be visible again before getting text from
it.
More discussion here:
https://chat.zulip.org/#narrow/channel/43-automated-testing/topic/stream.20create.20puppeteer.20failure/near/1976724
Co-authored-by: Anders Kaseorg <anders@zulip.com>
cb6c60ef7a