Added files from addon-test-support to addon.publicEntrypoints()

Features

• When a v1 addon has addon-test-support, the codemod adds its files to addon.publicEntrypoints(). In other words, the codemod takes care of a configuration step for rollup.config.{js,mjs}.¹

^{1. See #11 to learn how to keep your v2 addon up-to-date.}