Export fails, but doesn't error, when solution file is missing

[ineternet]

Tested versions

4.2.1.stable (mono)
4.2.2-rc (mono) (d5064a7)

System information

Godot v4.2.1.stable.mono - Windows 10.0.19045 - Vulkan (Forward+)

Issue description

When exporting a project and the .sln file is not where expected, nothing is reported to the user.
The export finishes, seemingly successfully, but the necessary .NET binaries are not included in the export, making it crash on startup. It seems that dotnet publish is never invoked.

It would be helpful if the export fails and also reports a descriptive error. The editor can not handle a missing solution file. Currently it is practically impossible to figure out something went wrong.

Furthermore, when using the --headless --export settings, a zero exit code is reported when this happens. This is probably already tracked in #83042 though.

Steps to reproduce

1. Create project
2. Create solution (Project -> Tools -> C#)
3. Create a new scene, and make it the main scene
4. Attach a C# script to the scene
5. Rename the solution file
6. Create an export profile that relies on dotnet publish, e.g. Windows Desktop
7. Run the export in an empty directory
8. Start the newly exported game

The game binary crashes on startup with exception 0xc0000005 (access violation). This is because the .NET publish is missing.

Minimal reproduction project (MRP)

SlnProject.zip

The MRP already has the necessary setup (scene, script, export profile, missing solution file). The only thing left is to run the export using the profile.