Log last sign-in date when disabling guest users

Updated the log message in Invoke-CIPPStandardDisableGuests to include the guest's last successful sign-in date for better auditing and traceability.

Author: JohnDuprey

Modules/CIPPCore/Public/Standards/Invoke-CIPPStandardDisableGuests.ps1

@@ -68,7 +68,7 @@ function Invoke-CIPPStandardDisableGuests {
             foreach ($guest in $GraphRequest) {
                 try {
                     $null = New-GraphPostRequest -type Patch -tenantid $tenant -uri "https://graph.microsoft.com/beta/users/$($guest.id)" -body '{"accountEnabled":"false"}'
-                    Write-LogMessage -API 'Standards' -tenant $tenant -message "Disabling guest $($guest.UserPrincipalName) ($($guest.id))" -sev Info
+                    Write-LogMessage -API 'Standards' -tenant $tenant -message "Disabling guest $($guest.UserPrincipalName) ($($guest.id)). Last sign-in: $($guest.signInActivity.lastSuccessfulSignInDateTime)" -sev Info
                 } catch {
                     $ErrorMessage = Get-CippException -Exception $_
                     Write-LogMessage -API 'Standards' -tenant $tenant -message "Failed to disable guest $($guest.UserPrincipalName) ($($guest.id)): $($ErrorMessage.NormalizedError)" -sev Error -LogData $ErrorMessage