"Property sourceFileMap is not allowed."

`sourceFileMap` attribute is not implemented for the `godot-mono` launch configuration type?

**OS/device including version:**

Windows 10

**Issue description:**

Basically, [this](https://github.com/OmniSharp/omnisharp-vscode/issues/3953) is happening to me, but when I try the linked solution and add the `sourceFileMap` attribute to my `godot-mono` launch configuration it says "Property sourceFileMap is not allowed."
If I change the type to, for example, coreclr temporarily, it resolves that attribute fine (but obviously that wouldn't actually be able to launch my project correctly).
I need to use it because the `PathMap` setting doesn't work in VS Code otherwise. If I don't have `sourceFileMap` and I'm using `PathMap`, when I'm debugging in vs code and put a breakpoint anywhere, I get "Could not load source 'MapEditor.cs': No source available."