Leverage external ref's files with GenAI functions at entity level

[Jipegien]

Use case

File attached to external reference are currently listed in the "Content" tab of entities having this external ref.

But these files cannot be used with Ask AI function.

When using Ask AI function to summarize a file ou generate a stix bundle, files from external ref of the entity should be take into account and selectable.

[Jipegien]

possible tiny