build(deps-dev): bump scratch-vm from 21915f4 to 19c9e8f (#700)

Bumps [scratch-vm](https://github.com/TurboWarp/scratch-vm) from `21915f4` to `19c9e8f`.
- [Commits](TurboWarp/scratch-vm@21915f4...19c9e8f)

---
updated-dependencies:
- dependency-name: scratch-vm
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>