Create a GitHub Actions workflow for running visual regression testing

[desrosj]

A foundation for visual regression testing was introduced in [51989],

The test:visual script was added in [55459], and the tool used was later migrated Puppeteer to Playwright in [56926].

Initially there were not many tests, so the script was intended to be run locally only. But it would be good to run these more regularly in a GitHub Actions workflow as more visual regression tests are added (see #64671).