dillon1000/react

Don't override use-sync-external-store peerDeps (#22882)

Usually the build script updates transitive React dependencies so that
they refer to the corresponding release version.

For use-sync-external-store, though, we also want to support older
versions of React, too. So the normal behavior of the build script
isn't sufficient.

For now, to unblock, I hardcoded a special case, but we should consider
a better way to handle this in the future.