Broken image export when using `srgb` css function

[mbergen]

Describe the bug
Image export breaks when srgb (or other modern color functions) are used.

To Reproduce
Steps to reproduce the behavior:

1. https://liquipedia.net/honorofkings/User:Lolliftw/Sandbox/4
2. Enable darkmode
3. Click on share, either copy or download (more descriptive error on download)
4. Observe the error (notify and console)

Additional context
Probably introduced with #7479
Fix might be to switch to a more modern library like https://github.com/zumerlab/snapdom