How should this repo be type checked?

[zepumph]

From phetsims/chipper#1487 (comment), there are 10 errors when I run grunt check in phet-lib. I'm unsure what is expected, but likely we need to change some configuration.

[zepumph]

@jonathanolson @samreid and I looked at this today.

• tsc -b and tsc doesn't work in phet-vite-demo right now.
• We do NOT want to put this repo in the grunt check --all.
• Once we pursue "phase two" with this, where phet-lib exports js + typescript typesc, tsc will likely pass here, and should be added to check --all.