Tspconfig validation: Temp disable the requirement configuration check for tspconfig.yaml for .NET #10478
Description
We have enabled the configuration check in tspconfig.yaml for all services that using TypeSpec.
Confirmed with dotnet team, the current C# CodeGen still have some limitation to support MPG for some brown field services so for those services, we still need to fall back to Swagger approach to generate the SDK.
So let removed the check for .net configuration in tspconfig.yaml and make it as optional, no change other languages as it is still the requirement for the correct tspconfig.yaml.
cc @ArthurMa1978 and @maririos for awareness.