Essentials: Export interface PresetOptions

[tyankatsu0105]

Closes #

What I did

I export PresetOptions at addon/essentials.
This PR makes us allow to use type definition with JSDoc:

const config = {
  addons: [
    {
      name: "@storybook/addon-essentials",
      /**
       * @type {import('@storybook/addon-essentials').PresetOptions}
       */
      options: {
        ...
      }
    }
  ]
};

How to test

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"]

[kasperpeulen]

Thanks looks great! we have a feature freeze until the 7 release, and will get this in after that

[kasperpeulen]

Could you resolve the conflicts @tyankatsu0105? Then we will get it in!