Hm, this is good, but in light ofmatplotlib/matplotlib@1936c94 maybe we should just inline the old definition (so that we don't emit things like\mathdefault)?

I tried to keep the change minimal. Getting rid of the Matplotlib function might be a good idea, but I think it's something the maintainer needs to be interested in so it actually gets merged. I also lack some knowledge for this.

I rarely use tikzplotlib at the moment and created this fix when I needed it last year. But as a sporadic user and seeing that the repo isn't maintained, I'm not interested in pursuing this much further.