Delete public-api-test (#52342)

Summary:
Pull Request resolved: #52342

This diff deletes `public-api-test` for detecting changes in public API. It is replaced with public API snapshot validation (in D76340729) for better detection and understanding of changes that influence external interfaces.

Changelog:
[Internal]

Reviewed By: huntie

Differential Revision: D77531763

fbshipit-source-id: a8ef2b6f52fa6efb5b312598ea3e4746fc51e4ec

Author: coado