Followup to rB3834dc2f7b38 (where getting the proper particle system was fixed for the Adjust Last Operation panel in the Properties Editor). But since this operator can also be called from the 3DView, get a current particle system there as well. Without this, _all_ particle systems would be copied when executing from the 3DView (which was never really intended [operator description uses singular] -- it just happens to use `copy_particle_systems_to_object` internally as well -- same as the `Copy Active/All to Selected Objects` operators)). ref. T83317 Maniphest Tasks: T83317 Differential Revision: https://developer.blender.org/D12033