[FEATURE REQ] SdkTspConfiguration add rule to stop SDK emitter config exist in both service layer and sub service layer

### API Spec link

https://github.com/Azure/azure-rest-api-specs/issues/39532

### API Spec version

N/A

### Please describe the feature.

In the folder structure v2 multi-project case, we should not allow service to have SDK emitter config in both the service layer and the sub service layer.

See comments from https://github.com/Azure/azure-rest-api-specs/issues/39974#issuecomment-3844609100

Start with the SdkTspConfiguration entry point and read the linked API spec issues 39532 and 39974 for the multi-project hierarchy and expected behavior. Done means the service is rejected when SDK emitter configuration exists at both the service and sub-service layers.

Written by the indexing model from the issue text.