Removing docker_base_image parameter and variables (#21864)
### Description
Removing `docker_base_image` parameter and variables. From the Cuda
Packaging pipeline.
### Motivation and Context
Since the docker image is hard coded in the
`onnxruntime/tools/ci_build/github/linux/docker/inference/x86_64/default/cuda12/Dockerfile`
and
`onnxruntime/tools/ci_build/github/linux/docker/inference/x86_64/default/cuda11/Dockerfile`
This parameter and variable is no longer needed.
