Summary: `parseErrorStack` (which uses the `stacktrace-parser` package) can return null file names, line numbers and column numbers. This diff updates the associated types and adds explicit null checks in some call sites.
Reviewed By: rickhanlonii
Differential Revision: D16542176
fbshipit-source-id: b72c73c05b95df0bbcb5b5baa7bc2d42cff1e074