Refactor Playwright build and auth steps into separate CI jobs so the shards do not repeat work

[grahamlangford]

Motivation

• We introduced sharding to dramatically reduce the Playwright runtime but each shard has to run authentication
• Running the setup authentication once in a separate step that the Playwright shards inherit would further reduce the time needed to run tests
• Running the build once before all also would cut a lot of wasted time on each shard.

Acceptance Criteria

• [ ] The GitHub Actions end-to-end-tests workflow first runs a separate build job, which is used in all subsequent playwright test runs.
• [ ] The setup projects (i.e. chromeSetup and edgeSetup) run in a separate job before all other shards.
  • [ ] Uploads the resulting profiles to Github artifacts, which are then pulled in each shard job.
  • [ ] The final report should still include the setup tests status and we should still be able to view the playwright report and traces for it.

More details

https://github.com/pixiebrix/pixiebrix-extension/blob/68615326daa77c0a2e8cb885773ea1dc72edac92/.github/workflows/end-to-end-tests.yml

Use the --no-deps and --project cli options https://playwright.dev/docs/test-cli