Setting interface/editor/custom_display_scale editor setting to NAN crashes the editor on restart and makes project manager totally unusable.

[ghost]

Godot version

v4.2.dev3.official.013e8e3af

System information

Windows 10.0.19045 - GLES3 (Compatibility)

Issue description

Warning: it is impossible to undo the following changes the same way that they are set!

Setting interface/editor/display_scale to "Custom" and interface/editor/custom_display_scale to NAN and then clicking "Save & Restart" button makes the editor crash with the following errors being printed:
editor.log

Trying to open Godot project manager again results in the following errors:
project-manager.log
As well as causes the project manager to display a blank window.

Here's a reproduction video:

recording.mp4

Steps to reproduce

0. Open Godot editor.
1. Set interface/editor/display_scale to "Custom".
2. Set interface/editor/custom_display_scale to NAN.
3. Click "Save & Restart".
4. Try to reopen the editor.

Minimal reproduction project

N/A

[YuriSizov]

Fixed by #81076.