Entity type filter values are not restricted in Relationship creation form list

[Archidoit]

Description

Entity type filter in Relationship creation form list from Knowledge tab of an entity should only propose possible values

Reproducible Steps

• Go to a malware Knowledge tab
• Go under 'Threat actors'
• in the list, only threat acotr individuals and threat actor groups are displayed
• Add a filter on 'entity type'
• All the entity types are proposed in the filter list, whereas we should only have the possible ones (Threat Actor Group and Threat Actor Individual in this case)

Same for other screens of Knowledge

[Jipegien]

limit the option to Threat Actor (Group) and Threat Actor (Individual)