System font should override user-specified fonts when it is the redacted font

[alice-mkh]

Prerequisites

• [x] I have searched open and closed issues for duplicates.

Describe the bug

Screenshot tool has a "Conceal text" feature. However, it doesn't work with Code text area.

To Reproduce

Steps to reproduce the behavior:

1. Run Code, get some text in it
2. Run Screenshot
3. Check 'Conceal text'
4. Do a screenshot. It will still show visible text inside the editor.

Expected behavior

Conceal text works as expected.

• [x] I'm using the latest version from git that I've manually compiled
• [x] I'm using the latest released stable version

[alice-mkh]

A part of the issue is that it doesn't listen to global font setting changes, just like terminal.

But then there's custom font preference. Terminal has it as well, but at least it's hidden there. And then, Code also effectively uses it for zooming. All in all, it means it's extremely easy to have a state where conceal text won't work even if Code did listen to global font changes.

While zooming can be implemented in a way that doesn't mess up that preference, I wonder if redacted font should be applied regardless of custom font used.