chore: skip if package already built

[agoose77]

hatch-jupyter-builder always runs by default, unless we set skip-if-exists

[agoose77]

@artur-trzesiok The reason this PR is needed is because hatch-jupyter-builder runs a build by default, even if the SDist contains the k3d/labextension build output already. This PR changes that, by skipping the build if the k3d/labextension/package.json exists.

This is partly happening because we don't have to ship the compiled artefacts in the SDist; we could only ship the source, and require that the user has nodejs installed. This is my preferred approach to packaging, but in #395 (and #386) we explicitly include the generated files in the SDist.

What is your preferred solution here? Would you prefer smaller SDists that require compilation, or to ship the compiled JS?

[artur-trzesiok]

But sdist include compiled js. Please check my k3d-2.15.0.tar.gz :
filestructure.txt

And sdist is still in good size (9.5mb). I don't need to make in smaller. K3D is a python package so I don't want to force users to use nodejs

[artur-trzesiok]

I assume that after that merge we should deploy 2.15.1 to trigger conda-forge process

[agoose77]

@artur-trzesiok yes, probably. Apologies for the confusion. Let me first confirm that this sdist doesn't require nodejs