Pushing gravity load gives a null error

#### Description:
When pushing a gravity load, that works when pushing to Robot, it does not push the loading to RFEM6 due to an error.
It seems similar to the issue with geometrical line load, which gets an additional fragment to determine whether it is a free- or nonfreelineload.

#### Steps to reproduce:
Any structure to push with gravity load. See example issue script.

#### Expected behaviour:
Preferably that it automatically pushes correct loading information, such that existing scripts don't need to editing with additional fragments. Although, the fragment solution might prove a good quick fix.

#### Test file(s):
https://burohappold.sharepoint.com/:p:/r/sites/Direction/designtechnology/RandDWishlist/00533_Increased_computational_workflow_STR/03_Workflows/01_Guidance/240111%20STR%20standard%20workflow%20guidance.pptx?d=w4edfb8794b9b48569056c25b03dddc2d&csf=1&web=1&e=TEIKt9