Build output says it is building a net45 project, but it is not

### Describe the bug

Traversal-only projects output a bogus .net target version

### To Reproduce

Due to the .sln build bugs we currently build out of a project file. `build\traversal\build.proj` looks like this:

```

```

All projects reference `net10` or `net10-windows`.

Build output is starts with the following line:

`... formbuilder\build\traversal\tmp.proj net45 win-x64`

Current SDK version is 10.0.103; but the bug seems to have been there ever since at least .NET 9.

### Expected output

`... formbuilder\build\traversal\tmp.proj win-x64`

Why? Because the travesal project itself has no targets, no build output, and therefore no .NET version. These are the build artifacts generated by the project file:

```
Volume in drive ? is Data Storage
Volume Serial Number is D11D-F444
Directory of ...\formbuilder\build\traversal\obj

01/16/2026 11:35 AM .
02/04/2026 07:31 AM ..
01/16/2026 11:35 AM 2,069 build.proj.nuget.dgspec.json
01/16/2026 11:35 AM 1,306 build.proj.nuget.g.props
11/21/2025 10:02 AM 150 build.proj.nuget.g.targets
01/16/2026 11:35 AM 2,148 project.assets.json
01/16/2026 11:35 AM 196 project.nuget.cache
5 File(s) 5,869 bytes
2 Dir(s) many bytes free
```