Build vllm and trtllm serially

Signed-off-by: Charlie Truong <chtruong@nvidia.com>

Author: chtruong814

docker/Dockerfile.trtllm_vllm

@@ -83,7 +83,7 @@ RUN git clone https://github.com/NVIDIA/TensorRT-LLM.git . && \
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-FROM base AS trtllm_builder
+FROM vllm_wheel AS trtllm_builder
 
 ARG TRT_VER
 ARG CUDA_VER