Update the 'use existing Entra ID app registration' to include the 'app registration name' as an additional field.

In the current form when deploying a new instance of Nerdio, when you click on ‘Show Advanced’ and click ‘Use existing Entra ID app registration’, the form only includes ‘App ID’, ‘App Secret’, & ‘Service Principal ID’ and when you ‘download script’, it auto-assumes the Nerdio App Registration name which is odd when we're specifying a custom app registration. 

This request is to add a new field which allows the admin to update the $appName variable with a custom name.