Update to npm-run-all2 causing issues

[MelSumner]

This PR: #368 had tests passing, so I felt safe to merge it. However, I think this needs a bit more investigation.

1. after merging, I was getting npm-run-all not found error messages when I pulled the main branch down locally and ran pnpm start.
2. I thought it was just related to the package.json scripts, but even after updating them to use npm-run-all2 instead of npm-run-all, I was still getting the error message when running pnpm start
3. I reinstalled npm-run-all as a devdep, just in case it's something an Ember script needed (leaving the package.json updated)
4. Everything builds and tests run locally, but were failing in the PR (tests run via GitHub action)

Since I don't see anything in the action right now, I've changed the scripts in package.json back to the way they were (using npm-run-all), but am leaving both devdeps there for the time being.

Want to help figure out what's going on? Help is welcome!

[aklkv]

will be fixed in #390