In CI, check for TS errors in built server code (of example app) by running `npx tsc`

[infomiho]

We want to make sure that there not TS errors in the built server app (e.g. our TODO app example) by running npx tsc.

Right now, we have some TS errors that we didn't really handle and we should make sure that our CI is passing once we introduce this check.

[Martinsos]

https://github.com/wasp-lang/wasp/blob/main/waspc/examples/todoApp/ensure_app_compiles_and_builds.sh

client, server .