This function only needs to duplicate the geometry of the boundary (every study plan must have its own boundary according to the current logic).
Duplicating this geometry should include a note to say which experiment boundary (with revision version) the geometries have been copied from (similar to the functionality for duplicating proposals)
We agreed that at the same time as addressing this issue, we would also address #688 to complete all the outstanding issues associated with experiment boundaries
Following issue https://github.com/Rothamsted-Ecoinformatics/farm_rothamsted/issues/693 we would ideally also be able to copy the experiment boundary from one study plan to another.