feat(wellknown): add external data share to wellknown

[CatalinDabuleanu]

📥 Pull Request

❓ What are you trying to address

Implement External Data Share to Wellknown JSON

[Copilot]

Pull Request Overview

This PR adds external data share functionality to the wellknown configuration by implementing a new function to retrieve external data shares and incorporating the results into the wellknown JSON structure.

• Adds Set-ExternalDataShare function to fetch external data shares from Fabric REST API
• Integrates external data share information into the wellknown configuration object
• Uses the first external data share from the lakehouse for the wellknown entry

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}