[FEAT] Promote triangle._dimensionality to public property

[genedan]

There's now an external use case with the Styler (only works on single triangles). I think external code might also find this attribute to be useful so they don't have to infer it from Triangle.shape.

I don't really see the harm in having this be a public property, let me know if you do.

[priyam0k]

Triangle.dimensionality is actually already available as a public property, so we can use that directly. I can put together a PR to update the references in Styler and the tests if that sounds good.

[genedan]

Looks like the public property is just a wrapper to the private one, so it seems redundant. How about we just remove the wrapper and then convert the private property to a public one?

[priyam0k]

That's much cleaner, we can promote _dimensionality directly to dimensionality and remove the redundant wrapper, updating the internal references across the repo.