Telemetry: Ensure we report errors even when unexpected things happen

[tmeasday]

Closes #21318

What I did

• Pass empty string if error.message is undefined (this happens with compilation errors):

• try/catch getting error level (this throws if main.js has syntax errors):

How to test

1. Run a sandbox for template, e.g. yarn task --task sandbox --start-from auto --template react-vite/default-ts
2. Add syntax error to preview.js
3. Run with STORYBOOK_TELEMETRY_DEBUG=1 yarn storybook

Also try - 2. add syntax error to main.js

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

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

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