New Sample - Cleanup a SPFx Solution from every Site and App Catalog

[fabianhutzli]

This PR adds a new PnP PowerShell script that fully removes a SPFx solution from a SharePoint Online tenant.

The script covers the complete cleanup flow:

• Iterates over all site collections in the tenant
• Uninstalls the app from every site where it is actively deployed
• Clears matching recycle bin entries per site (apps land there after uninstall)
• Removes the app package from the tenant app catalog
• Clears the app catalog recycle bin to ensure no package remnants remain

This is useful when you need a complete removal before a reinstall, or when retiring a solution tenant-wide.

Script details

• Tool: PnP PowerShell
• Product: SharePoint Online
• Category: Deploy
• Commands used: Get-PnPTenantSite, Get-PnPApp, Uninstall-PnPApp, Remove-PnPApp, Get-PnPRecycleBinItem, Clear-PnPRecycleBinItem