Add Chromatic visual testing to our site/E2E tests

Chromatic has [introduced visual testing for Playwright](https://www.chromatic.com/playwright). We should explore adding this additional layer of user flow bug detection to our current E2E tests within `site/e2e`.

**Requirements:**

- [ ] Add manual snapshots to each of our E2E tests as appropriate - these can be component snapshots or full page snapshots
- [ ] Remove any redundant storybook component tests (if there are any)
- [ ] Add a NPM script to our `package.json` for running Chromatic with the `playwright` flag
- [ ] Update our CI workflow's Chromatic setup such that it also supports Playwright
- [ ] Update our FE README to make mention of this new tooling
- [ ] Establish baseline speed of our CI run and then compare after we have added this layer - it is important we don't significantly slow down the job considering these tests are run on every PR.
- [ ] Understand monthly cost of these additional snapshots as Chromatic's pricing depends on # of snapshots - is this addition going to move the needle significantly?

Start by reading the existing tests in site/e2e and package.json, then locate the current Chromatic setup in the CI workflow. Add appropriate Playwright snapshots, the requested script and CI support, remove redundant Storybook tests, and update the FE README. Compare CI speed before and after, and document the expected snapshot cost.

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