Update profile.ps1 to include -ErrorAction Stop in Connect-AzAccount -Identity when the user authenticates with Azure PowerShell using an MSI

I've investigated a CRI in which a worker VM went in a bad state and the function app experienced DNS resolution errors. As a result, the function could not connect to the Azure back end service.

We should update the `profile.ps1` to ensure that if `Connect-AzAccount -Identity` fails, the function execution stops. We can accomplish this by adding `-ErrorAction Stop`.

In addition, we should also consider adding a new line as a comment where the user sets the Azure PowerShell context to the required subscription.

```powershell
if ($env:MSI_SECRET) {
Disable-AzContextAutosave -Scope Process | Out-Null
Connect-AzAccount -Identity -ErrorAction Stop
# Get-AzSubscription -SubscriptionId -ErrorAction Stop | Set-AzContext -ErrorAction Stop
}
```

This template update should be applied to the Azure Portal, Core Tools, and VSCode Extension.