Core: bail preview builder on failure

[yannbf]

Issue: N/A

What I did

For some reason, even when Webpack fails (e.g. wrong main.js config), the preview may continue to print to stdout, which can affect output when we catch this error and process those errors (e.g. telemetry) gets overwritten by preview progress output. Therefore, we should bail the preview too.

An example to get into this situation is using a CRA project without @storybook/preset-create-react-app

The user experience is the following:

• There's a misconfiguration which makes it so that Storybook partially fails. For instance, missing babel presets. This is not a fatal failure, though it should because presets require rerunning the server.
• Storybook is not automatically opened, but can be accessed:

- The Storybook server says `WARN Force closed manager build` in the terminal - If crashReports were never answered, the telemetry prompts the user "would you like to send reports". However, immediately after that happens, Webpack continues with preview's progress, which in turn, ovewrites the stdout, therefore never showing the telemetry prompt - Because there is a prompt, the process is hanging, but the user doesn't even know why as they don't see the actual message. Only after pressing either Y, N or Ctrl+C, the process continues and the failures are shown. - This won't happen again in case users responded with Y or N, because that answer is saved in the cache.

How does it look like?

So the fix now interrupts the preview process output, therefore showing the prompt correctly:

And after the prompt is answered (and answer is cached), the other times the failure happens, users will get the errors directly:

How to test

• Is this testable with Jest or Chromatic screenshots?
• Does this need a new example in the kitchen sink apps?
• Does this need an update to the documentation?

If your answer is yes to any of these, please make sure to include it in your PR.