"You must install .NET to run this application" on 13.4 and 13.5 preview on nixos

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Describe the bug

I receive an error:

> You must install .NET to run this application.
>
> App: /home/rei/sync/source/Ronin/Ronin.AppHost/bin/Debug/net10.0/Ronin.AppHost
> Architecture: x64
> App host version: 10.0.8
> .NET location: Not found
>
> The following locations were searched:
> Application directory:
> /home/rei/sync/source/Ronin/Ronin.AppHost/bin/Debug/net10.0/
> Environment variable:
> DOTNET_ROOT = /nix/store/df9rnnw10lia4wlfdjn0n4zii8gpsrb1-system-path/bin
>
> Learn more:
> https://aka.ms/dotnet/app-launch-failed
>
> Download the .NET runtime:
> https://aka.ms/dotnet-core-applaunch?missing_runtime=true&arch=x64&rid=linux-x64&os=nixos.26.05&apphost_version=10.0.8

It was fine until 15.3. I tried setting DOTNET_ROOT:

```shell
export DOTNET_ROOT="$(dirname $(which dotnet))"
```

but that made no difference other than to the error message, which indicates the path.

### Expected Behavior

It runs.

### Steps To Reproduce

_No response_

### Exceptions (if any)

_No response_

### Aspire doctor output

_No response_

### Anything else?

_No response_