Load Errors window is not scaling properly (hidpi)

[afiestas]

Operating system or device - Godot version:
Archlinux, godot from git

Issue description (what happened, and what was expected):
I was checking out the new hidpi support (kudos for that) and I noticed that one of the windows is not scaling

Steps to reproduce:
Make the Load Error window appear.

Link to minimal example project (optional but very welcome):

[reduz]

I fixed this a while ago, though I can't find the commit