fix: use getFile() to obtain file node in loadCertDataFromLibreSignFile

Fix bug where fopen() was called on database File entity instead of
filesystem File node, causing 'fopen does not exist' errors in validation.

Signed-off-by: Vitor Mattos <[email protected]>

Author: vitormattos

lib/Service/FileService.php

@@ -320,7 +320,8 @@ private function loadCertDataFromLibreSignFile(?File $file = null): void {
 			return;
 		}
 
-		$resource = $file->fopen('rb');
+		$fileNode = $this->getFile();
+		$resource = $fileNode->fopen('rb');
 		$sha256 = $this->getSha256FromResource($resource);
 		if ($sha256 === $file->getSignedHash()) {
 			$this->pkcs12Handler->setIsLibreSignFile();