Enhance motion forward dialog part 2

[Elblinator]

see OpenSlides/openslides-backend#2519 for context

If a motion with change recommendations is forwarded (as motion type original with...) then the change recommendations become a part of the original motion

The change recommendations should stay distinct change recommendations

Dependent on the backend (if a new flag is created or sth else) the client needs to change the payload to the backend accordingly