Remove --extra-index-url (#19885)

### Description
<!-- Describe your changes. -->



### Motivation and Context
--extra-index-url is not allowed by injected Secure Supply Chain Step in
packaging pipelines.
```
> Starting Multifeed Python Security Analysis:
##[warning]tools/ci_build/github/azure-pipelines/bigmodels-ci-pipeline.yml - Found "extra-index-url". (https://aka.ms/cfs/pypi)
```
And those 2 packages can be installed from PyPI as well now.

Co-authored-by: Yi Zhang <your@email.com>

tools/ci_build/github/azure-pipelines/bigmodels-ci-pipeline.yml

@@ -25,7 +25,7 @@ pr:
     - BUILD.md
     - 'js/web'
     - 'onnxruntime/core/providers/js'
-#### end trigger ####parameters:
+#### end trigger ####
 
 # reference: https://github.com/microsoft/onnxruntime/blob/main/onnxruntime/python/tools/transformers/models/stable_diffusion/README.md
 parameters:
@@ -214,7 +214,7 @@ stages:
             python3 -m pip install /Release/*.whl; \
             pushd /workspace/onnxruntime/python/tools/transformers/models/stable_diffusion; \
             python3 -m pip install -r requirements-cuda11.txt; \
-            python3 -m pip install --upgrade polygraphy onnx-graphsurgeon --extra-index-url https://pypi.ngc.nvidia.com; \
+            python3 -m pip install --upgrade polygraphy onnx-graphsurgeon ; \
             echo Generate an image guided by a text prompt; \
             python3 demo_txt2img.py --framework-model-dir /model_cache --seed 1 --deterministic "astronaut riding a horse on mars" ; \
             find $(pwd)/ORT_CUDA -name "*.png" -exec cp {} /images/ \; ; \