docs: debug Jest tests using Playwright (Chromium)

[MadLittleMods]

Add docs for debugging and seeing errors that occur in Jest tests using Playwright -> Chromium. See devtools console output

Spawned while working on #7097. These steps were necessary to see what was actually going wrong in these cases.

Recent related PR: #7082

Description

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[patak-dev]

Thanks for these PRs @MadLittleMods! And thanks for your work to push forward Matrix, it was great to see that Hydrogen is using Vite ❤️

[MadLittleMods]

Thank you for the super fast review and merge @patak-dev 😊