Add DS-Chat CI workflow (#4127)

* Add DS Chat CI workflow

* Add CRITIC_CKPT_DIR env variable to actions.yml

* Update step 2 opt 125m ckpt dir name

* Update test dir

* Add workflow_dispatch

* Add :

* Add nv-ds-chat badge to main README

* Open GH issue if DS Chat CI fails

* Remove pull_request and merge_group conditions

* Update and test torch version

* Remove PR trigger

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Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>