ci: Use nvcr.io image for sglang base container (#3996)

Signed-off-by: Dillon Cullinan <dcullinan@nvidia.com>
Signed-off-by: Tushar Sharma <tusharma@nvidia.com>
Co-authored-by: Tushar Sharma <tusharma@nvidia.com>

container/Dockerfile.sglang

@@ -39,8 +39,7 @@ FROM ${DYNAMO_BASE_IMAGE} AS dynamo_base
 # - Develop or debug framework-level components
 # - Create custom builds with specific optimization flags
 #
-
-FROM nvidia/cuda:${CUDA_VERSION}-cudnn-devel-ubuntu24.04 AS framework
+FROM nvcr.io/nvidia/cuda:${CUDA_VERSION}-cudnn-devel-ubuntu24.04 AS framework
 
 # Declare all ARGs
 ARG BUILD_TYPE=all