Resolve js-yaml security advisory

[Yuto-24]

Summary

• Update ESLint-related devDependencies so js-yaml can resolve to a patched version.
• Add npm override for @istanbuljs/load-nyc-config to force js-yaml@4.2.0.
• Keep the fix scoped to the js-yaml security advisory.

Verification

• npm ls js-yaml
  • confirmed js-yaml@3.14.2 is no longer present
  • confirmed js-yaml@4.2.0 is used
• npm test
  • passed

Notes

npm run build currently fails during the webpack step due to an existing webpack / gas-webpack-plugin compatibility issue. That build issue is tracked separately and is intentionally out of scope for this security advisory fix.