onnxruntime

Add helper to run CIs for a branch using `az pipelines`. (#16843)

### Description
<!-- Describe your changes. -->
Add helper to run CIs for a branch using `az pipelines`.
This can be used to easily kick off multiple CIs for a branch prior to
creating a PR.

Update run_CIs_for_external_pr.py so the CI list can be shared. 
Request json output from `gh pr view` so the current state is more
easily parsed.

### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->