web: run puppeteer only if `client` is affected
Created by: valerybugakov
Puppeteer tests take a lot of time. Since we mock API responses, changes that do not affect client
won't change Puppeteer tests results. This PR disables Puppeteer tests if client
is not affected in the diff. It uses the same logic we apply to skip Chromatic visual tests.
Tested CI pipeline with different changes in this test PR.
Closes https://github.com/sourcegraph/sourcegraph/issues/20880. Slack thread.