Resolve #3455540 "S3fs compatability fixes"

src/Plugin/Field/FieldFormatter/CSVFileFormatter.php

@@ -526,7 +526,7 @@ class CSVFileFormatter extends FileFormatterBase {
           }
 
           // Render HTML table from CSV file.
-          $file_name = $this->getFileSystem()->realpath($file->get('uri')->value) ?? $file->getFileUri();
+          $file_name = $this->getFileSystem()->realpath($file->get('uri')->value) ?: $file->getFileUri();
           $table_data = $this->readcsv($file_name, $field_name . '-' . $item_count, $item->getEntity()->id(), $item->description);
           $elements[$delta][$elemcount] = $table_data;