fix(migration): Make naming constraint fail softer on updates
Only on installation we want to break hard, so that all developers notice
the bugs when installing the app on any database or CI, and can work on
fixing their migrations before releasing a version incompatible with Postgres.
In case of updates we might be running on production instances and the
administrators being faced with the error would not know how to resolve it
anyway. This can also happen with instances, that had the issue before the
current update, so we don't want to make their life more complicated
than needed.