Fix the Playwright workflow

[ptgott]

I've noticed that:

• The .github/workflows/playwright.yml workflow either always fails or is always skipped
• This doesn't stop us from merging gravitational/docs PRs

We should clean up the Playwright workflow so the gravitational/docs GHA pipeline is easier to understand. This could mean either:

• Getting Playwright tests to pass and ensuring that gravitational/docs PRs block on these tests passing
• Removing the Playwright workflow altogether
• Incorporating the Playwright tests into the Storybook test suite (i.e., rewriting these as Storybook tests). Then ensure that our Storybook tests block gravitational/docs PRs if they fail