Log which SDK Build Servers are shutting down from `dotnet build-server shutdown`

### Is your feature request related to a problem? Please describe.
running `dotnet build-server shutdown` shuts down the MSBuild server, VB/C# compiler and Razor compiler, for the _specific_ .NET SDK that is resolved by the dotnet process, based on the current directory, global.json etc, terminal context (e.g. VS Console).

This is an example output from the command:
```shell
> dotnet build-server shutdown
Shutting down MSBuild server...
Shutting down VB/C# compiler server...
MSBuild server shut down successfully.
VB/C# compiler server shut down successfully.
```
This gives no indication of which SDK's build servers have been shut down.

For example, I run `dotnet build` in a folder with a .NET 9 project, specified with a global.json to use the .NET 9 SDK.
After running, I can see the MSBuild nodes running:

Makes sense so far.

Now, I open a new terminal, which defaults to `C:\Windows\System32`.
Running `dotnet build-server shutdown` yields the same output as above. However, the MSBuild nodes remain running.

If I run `shutdown` from the same folder as where I ran `dotnet build`, the processes are killed correctly :)

### Describe the solution you'd like
This behaviour makes sense if you know how MSBuild and the SDK resolution works, but I think it would be much clearer to add a log line such as:
```shell
Shutting down build servers for the .NET 9.0.303 SDK
```
And potentially disambiguate between regular SDKs and VS SDKs.