chore(backstop): script to work with puppeteer chrome version - #7772

$ yarn backstop:chrome

To make changes to the chrome version puppeteer uses, reference https://pptr.dev/browsers-api
For a list of the current "Chromium for Testing" versions, reference https://googlechromelabs.github.io/chrome-for-testing/

Some common commands:
- npx @puppeteer/browsers list # lists all installed browsers
- npx @puppeteer/browsers clear # removes all installed browsers
- npx @puppeteer/browsers install chrome@stable # install specific chromium version
 - Available options are: stable, beta, dev, canary, and a specific version (eg, 139.0.7258.154)

Puppeteer is using: Chrome/139.0.7258.68