CSV import crash when importing duplicate _EFFET_INDESIRABLE_

[nathanaelhoun]

Describe the bug

CSV import crashes when importing a file with a duplicate EFFET_INDESIRABLE value for a molecule.

To Reproduce

1. Create a CSV file with a duplicate EFFET_INDESIRABLE value for a molecule
2. Import the CSV throught the admin UI.
3. Validate the import
4. See the error