Fix timing of `remove_all_duplicates` in `Delaunay3D` class

[tkoyama010]

Overview

The gmsh.model.geo.remove_all_duplicates() function is used to remove duplicates, but it should be called at the appropriate time. Generally, this should be done after defining all geometry and before the final synchronize().

Details

• found in #313

[tkoyama010]

@all-contributors please add @tkoyama010 for code

[allcontributors[bot]]

@tkoyama010

@tkoyama010 already contributed before to code

[tkoyama010]

LGTM