Make tests less flaky

[GrygrFlzr]

Combines most .click tests with .waitForNavigation, which stabilizes the tests somewhat.

[Conduitry]

Running the promises in parallel sounds like it'd be asking for another race condition. We shouldn't be awaiting the page navigation promise once we've already awaited the click promise?

[GrygrFlzr]

This was the recommended solution from the playwright docs and was actually to avoid a race condition:

Clicking an element could trigger asynchronous processing before initiating the navigation. In these cases, it is recommended to explicitly call page.waitForNavigation([options]). For example:

• Navigation is triggered from a setTimeout
• Page waits for network requests before navigation

// Note that Promise.all prevents a race condition
// between clicking and waiting for a navigation.
await Promise.all([
  page.waitForNavigation(), // Waits for the next navigation
  page.click('a'), // Triggers a navigation after a timeout
]);

Presumably because it's possible for the click to finish processing before we call waitForNavigation(), in which case it'll just time out after 30 seconds.

I also ran the CI on ubuntu + macOS on node 12 + 14 + 15 and it succeeded three times in a row, so either I got really lucky or it's slightly better off.