fix: restore .value access when using -AllPages on group queries

Invoke-GraphRequest with -AllPages returns the full response object
with accumulated items in .value, not a flat array.

Scripts/Export-AssignmentsToCsv.ps1

@@ -243,7 +243,7 @@ if(-not $selectedTypeTitles)
 
 Write-Host "`nLoading groups for name resolution..." -ForegroundColor Cyan
 $groupsResponse = Invoke-GraphRequest "/groups?`$select=id,displayName&`$orderby=displayName" -AllPages
-$groups = $groupsResponse
+$groups = $groupsResponse.value
 
 $reportRows = @()