Sightings tabs in observables are broken

[Lhorus6]

Description

Sightings tabs in the Observables are broken:

• Sightings are not displayed
• It is not possible to create new Sightings

Environment

OCTI 6.3.3

Reproducible Steps

Steps to create the smallest reproducible scenario:

1. Go on a Country and in the "Sightings" tab
2. Create a new sightings with an IPv4 Observable
3. Go on the IPv4 and in the "Sightings" tab -> You can't see the newly created sightings and you can't create new sightings

[nino-filigran]

I canto fully reproduced sicne, in demo for whatever reason, you cannot select the list of observable you want:

I've created a sighting from a country, selecting an artifact. Sighting was created & visible in the artifact's sgihting tab. But when navigating to the artifact's sighting tab, I could not created a new sighting indeed.

Therefore the fix should be:

• allow the selection of any observable in the list when creating a sighting
• ensure that we can add a sighting from the sghting tab of an observable after having created one.