Update surface property of a surface groupe

[Picaut]

The value of the surface of a given surface group (origin) seems not updated when moving surface elements to a group

[Picaut]

Seems updated when closing and opening the project

[nicolas-f]

The area is updated when the user select a face group after dropping the face.

[Picaut]

Not resolved and a bug occurred when moving surface elements from a group to another one. Surfaces disappeared. Project file was closed and reopened to make re-appearing surface element in the tree project.