telemetry: improve addon extraction logic

[yannbf]

What I did

This PR changes the logic in extracting addon names, which were not entirely correct before, e.g. :

'@storybook/preset-create-react-app',
'@storybook/addon-ends-with-js/preset.js',
'@storybook/addon-postcss/dist/index.js',

Similar logic has to be implemented in the eslint-plugin too. Perhaps the addon extraction from main.js + sanitization should be a utility in a package shared between them?

How to test

Run yarn test storybook-metadata

• 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.

[shilman]

Looks great!