fix(security): upgrade serialize-javascript to 7.0.3 to fix RCE [APS-18800]

- Add npm `overrides` block in package.json forcing serialize-javascript
  to 7.0.3 (transitive dep via mocha; cannot bump directly).
- Regenerate package-lock.json. npm 10 upgraded lockfileVersion 1 -> 3
  (required for `overrides` to take effect).
- Resolves GHSA-5c6j-r48x-rmvq (CVSS 8.1) — RCE via RegExp.flags and
  Date.prototype.toISOString().
- npm ls confirms: serialize-javascript@7.0.3 overridden.
- Test suite: 663 passing, 13 failing, 2 pending — IDENTICAL to master
  baseline. No regression introduced.

Resolves: APS-18800

Author: karanshah-browserstack