[Documentation] Updates to NVIDIA Playground/Foundation Model naming.… (#14770)

…  (#14723)

- **Description:** Minor updates per marketing requests. Namely, name
decisions (AI Foundation Models / AI Playground)
  - **Tag maintainer:** @hinthornw 

Do want to pass around the PR for a bit and ask a few more marketing
questions before merge, but just want to make sure I'm not working in a
vacuum. No major changes to code functionality intended; the PR should
be for documentation and only minor tweaks.

Note: QA model is a bit borked across staging/prod right now. Relevant
teams have been informed and are looking into it, and I'm placeholdered
the response to that of a working version in the notebook.

Co-authored-by: Vadim Kudlay <32310964+VKudlay@users.noreply.github.com>

.github/workflows/_release.yml

@@ -19,7 +19,7 @@ on:
           - libs/experimental
           - libs/community
           - libs/partners/google-genai
-          - libs/partners/nvidia-aiplay
+          - libs/partners/nvidia-ai-endpoints
 
 env:
   PYTHON_VERSION: "3.10"