[17.0] fs_attachment unable to save Attachment Rules

[CasVissers-360ERP]

Module

fs_attachment

Describe the bug

https://app.screencastify.com/v3/watch/lNaDUColgK4gQw8GMvJY
Can't save additional attachment rules error seems incorrect.
@astirpe could you maybe help with a PR here?

Additional context
In addition I think we should consider adding .scss to the DB by default. This is used by Odoo website.
@lmignon could you maybe judge this?

[astirpe]

Seems the additional attachment rules issue is caused by the constraint that doesn't work well because of the constrained fields that are not stored on db (maybe issue of module server_environment?)
In #363 there's a quick fix, I didn't find a better way to solve it.

CC @CasVissers-360ERP