CLI: Gracefully shutdown and cleanup execa child processes

[valentinpalkovic]

Closes N/A

What I did

Execa child processes should be cleanup up as soon as the parent process quits. During initialization, the "cancel" event should properly be sent, and it should not lead to error events sent.

Also set the cleanup option to all our execa command executions, since I think the child processes shouldn't continue to run if the parent process exits.

How to test

1. Run the init event like STORYBOOK_TELEMETRY_DEBUG=1 <storybook-folder>/code/lib/cli/bin/index.js init --force in one of the sandboxes.
2. Exit at any time. The cancel event should be sent without any following error event or any other logs from e.g. yarn
3. The events should be logged to the console in the following order:

• boot(init)
• init
• boot(dev)
• dev
• nothing if I ctl-C

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli/src/sandbox-templates.ts
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "build", "documentation", "maintenance", "dependencies", "other"]

[yannbf]

I tested this flow in a react-vite sandbox:

1. Run STORYBOOK_TELEMETRY_DEBUG=1 <storybook-folder>/code/lib/cli/bin/index.js init --force
2. Wait until Storybook successfully runs after init
3. Ctrl C

The events were as following:

boot(init)
init
boot(dev)
dev
canceled(init)
error(init)

[valentinpalkovic]

@mrharispe Could be. Could you open a new issue and provide a reproduction, if possible?