Loads and validates solutions.
[ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception)
: Thrown when filePath is null or whitespace.[FileNotFoundException](https://learn.microsoft.com/dotnet/api/system.io.filenotfoundexception)
: Thrown when the solutions.json file does not exist.[InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception)
: Thrown when the configuration is invalid.