Add action to run npm audit for /playwright dependencies

[Matthew-Grayson]

🗣 Description

Adds vulnerability scanning for the /playwright directory's package files to GitHub Actions.

💭 Motivation and context

This change improves visibility of /playwright vulnerabilities in a way that compels developers to prioritize remediation.

We are using multiple vulnerable dependencies in our playwright implementation. The /playwright directory doesn't have Vulnerability checks setup to identify vulnerabilities when code is pushed. As of now, we have to rely on other indicators to find these vulnerabilities.

🧪 Testing

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.
• Bump major, minor, patch, pre-release, and/or build versions as appropriate via the bump_version script if this repository is versioned and the changes in this PR warrant a version bump.
• Create a pre-release (necessary if and only if the pre-release version was bumped).

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release (necessary if and only if the version was bumped).

[Matthew-Grayson]

Failing action check for vulnerabilities is remediated in PR #1170.