Feature: Run postVisit on failures

[yannbf]

Closes #

What I did

Experiment for allowing postVisit to be run on failures so you can do things like:

const config: TestRunnerConfig = {
  async postVisit(_page, context) {
    if(context.hasFailure) {
      console.log('problems!', context)
    }
  },
}

Checklist for Contributors

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• [ ] Add or update documentation reflecting your changes in this repository
• [ ] Request documentation updates in the test-runner docs website

Checklist for Maintainers

• [ ] Make sure this PR contains one of the labels below:

  Available labels

  - `skip-release`: Skip any releases, e.g., documentation only changes, CI config etc. - `patch`: Upgrade patch version (e.g. 0.0.x) - `minor`: Upgrade patch version (e.g. 0.x.0) - `major`: Upgrade patch version (e.g. x.0.0)

📦 Published PR as canary version: 0.19.2--canary.494.7268a7d.0

:sparkles: Test out this PR locally via: ```bash npm install @storybook/test-runner@0.19.2--canary.494.7268a7d.0 # or yarn add @storybook/test-runner@0.19.2--canary.494.7268a7d.0 ```