fix: PhpSpreadsheet exporters not utilizing the "value" view var

src/Bridge/PhpSpreadsheet/Exporter/Type/AbstractPhpSpreadsheetExporterType.php

@@ -54,7 +54,7 @@ protected function createSpreadsheet(DataTableView $view, array $options = []):
 
         foreach ($view->valueRows as $valueRow) {
             $this->appendRow($worksheet, array_map(
-                static fn (ColumnValueView $view) => $view->value,
+                static fn (ColumnValueView $view) => $view->vars['value'],
                 $valueRow->children,
             ));
         }