Update empty state documentation

[aaryanporwal]

Done

• Updated the introduction of the empty state component according to the copydoc: https://docs.google.com/document/d/1YoVeZU2fgSwiPmqidcMe4pQ_TnlIFS_3uHa4lIV3XPQ/edit.

Fixes WD-6189

QA

• Open demo
• [Add QA steps]
• Review updated documentation:
  • [List any updated documentation for review]

Check if PR is ready for release

If this PR contains Vanilla SCSS code changes, it should contain the following changes to make sure it's ready for the release:

• PR should have one of the following labels to automatically categorise it in release notes:
  • Feature 🎁, Breaking Change 💣, Bug 🐛, Documentation 📝, Maintenance 🔨.
• Vanilla version in package.json should be updated relative to the most recent release, following semver convention:
  • if CSS class names are not changed it can be bugfix relesase (x.x.X)
  • if CSS class names are changed/added/removed it should be minor version (x.X.0)
  • see the wiki for more details
• Any changes to component class names (new patterns, variants, removed or added features) should be listed on the what's new page.

Screenshots

[if relevant, include a screenshot or screen capture]

[bartaz]

@aaryanporwal The PR test is failing (due to formatting issues - likely unnecessary or unneeded empty lines) - could you run dotrun test locally and fix those?

Running Prettier via VS Code on the file should do it.

[bartaz]

@aaryanporwal There is a conflict (I guess because of my layout PR merged) and prettier check is failing on formatting of .md file.

[aaryanporwal]

Yup, I'll fix that.