Change the router to use peerDependency for fast-element

[janechu]

Pull Request

📖 Description

The @microsoft/fast-router is erroneously using @microsoft/fast-element as a direct dependency, this is causing issues during publishing and is the incorrect dependency structure for the package.

✅ Checklist

General

• I have included a change request file using $ npm run change
• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.