Add ABI package in FE+BE tsconfig.json?

[jon-lewis]

When performing the ABI v0.3.0 upgrade PR, there was some weird behavior with having a common typescript package (e.g. ./abi). Michael called out this behavior here.

It seems we can pull in a common TS package into the frontend without including it in the tsconfig.json (we have to do this for the backend). We would like to know why/how this is working for the frontend.

Is the backend compiling the @pc/abi code to the root node_modules and then the frontend project is using that cache? If so, we should probably include the ./abi files in the frontend/tsconfig.json.