identifiers: Fix some invalid ValidationError template string formats
Some ValidationError exceptions could not be serialized to string due to these format errors.
Related to swh-web#3234 (closed)
Migrated from D5492 (view on Phabricator)
Staging instance, all changes can be removed at any time
Some ValidationError exceptions could not be serialized to string due to these format errors.
Related to swh-web#3234 (closed)
Migrated from D5492 (view on Phabricator)