Add azure regen preview local script (#53624)

* build: add azure regen preview local script

* Update eng/packages/http-client-csharp/eng/scripts/RegenPreview.ps1

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* nits

* fix text

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: 2 people