Firebase Data Connect quickstart doesn't compile after cloning the repo

[thatfiredev]

When trying to open all of the quickstarts, the Data Connect one throws an error due to missing autogenerated files (similar to how the CI breaks in #1672 ), and prevents compiling the whole project.

We should find a way to make sure FDC doesn't prevent the project from compiling.

#2569 might be our best bet at the moment.