Exception "The SVG size is undefined" raised using svg2png

Converting the following SVG file (see code bellow) into a PNG caused an exception to be raised:

```
Traceback (most recent call last):
File "/Volumes/Test/main.py", line 12, in
cairosvg.svg2png(url=URL, write_to=OUTPUT_PATH)
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/__init__.py", line 55, in svg2png
return surface.PNGSurface.convert(
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/surface.py", line 133, in convert
instance = cls(
^^^^
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/surface.py", line 225, in __init__
self.draw(tree)
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/surface.py", line 472, in draw
self.draw(child)
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/surface.py", line 472, in draw
self.draw(child)
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/surface.py", line 480, in draw
paint_mask(self, node, mask, opacity)
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/defs.py", line 145, in paint_mask
mask_surface = SVGSurface(mask_node, None, surface.dpi, surface)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Volumes/Test/venv/lib/python3.12/site-packages/cairosvg/surface.py", line 209, in __init__
raise ValueError('The SVG size is undefined')
ValueError: The SVG size is undefined
```

Here is the code to reproduce:

```python
import cairosvg

URL = "https://upload.wikimedia.org/wikipedia/commons/3/32/Saltwater_Limpet_Diagram-en.svg"
OUTPUT_PATH = "output.png"
cairosvg.svg2png(url=URL, write_to=OUTPUT_PATH)
```

Start with the provided Python script and SVG URL, reproducing the failure through cairosvg.svg2png. Trace the reported path in cairosvg/surface.py around SVGSurface and mask handling, then add a regression test for this input; done means the SVG converts to PNG without the reported exception.

Written by the indexing model from the issue text.