fix: assign new mime type to sanitized uploads if applicable

src/Service/Upload/UploadHandler.php

@@ -141,7 +141,10 @@ class UploadHandler
             $sanitizedFilepath = $this->sanitizer->sanitizeFile($filepath);
 
             if ($filepath !== $sanitizedFilepath) {
-                $upload->setFilename(basename($sanitizedFilepath));
+                $upload
+                    ->setFilename(basename($sanitizedFilepath))
+                    ->setMimeType('application/pdf')
+                ;
             }
         } catch (\InvalidArgumentException $e) {
         }