Fix addMissingDependency (#98588)
While before this change we had addMissingDependency, we didn't properly
respond when the file for that missing dep was added.
The way webpack does this internally is not the exact same shape as the
IPC here, it has them as a separate field. I could not find any reason
not to just add them to the filePaths here. So that's what I did to keep
things simple.
