Also correct argument handling when Python arguments were passed in,
which were attempting to handle the following parameters as arguments
instead of skipping them.
As proposed in #98518, this moves all `View2D` files into
a `source/blender/editors/inteface/view2d/` directory. This helps
keeping the `interface/` directory clean. In general I think we should
promote a more modular thinking, where coherent parts of the code form a
module or sub-module. The directory structure and its files can reflect
that nicely.
Pull Request: https://projects.blender.org/blender/blender/pulls/132853
