fix: Adapt pdf service to new field api

Signed-off-by: Julius Härtl <jus@bitgrid.net>

[skip ci]

lib/Service/PdfService.php

@@ -9,7 +9,7 @@
 
 use mikehaertl\pdftk\Pdf;
 use OCP\Files\Node;
-use OCP\Files\Template\Field;
+use OCP\Files\Template\FieldFactory;
 use OCP\Files\Template\FieldType;
 use Psr\Log\LoggerInterface;
 
@@ -34,12 +34,14 @@ public function extractFields(Node $file): array {
 					continue;
 				}
 
-				$templateFields[] = new Field(
+				$templateField = FieldFactory::createField(
 					(string)$index,
-					$field['FieldValue'],
 					$fieldType,
-					alias: $field['FieldName'],
 				);
+				$templateField->setValue($field['FieldValue']);
+				$templateField->alias = $field['FieldName'];
+
+				$templateFields[] = $templateField;
 				$index++;
 			}
 			return $templateFields;