fix: do not publish unnecessary files

[charliecruzan-stripe]

Summary

we were including files that didn't need to be included bc package.json's files totally overrides .npmignore. So even though we were ignoring subdirectories, it didn't matter.

Removed files usage altogether, all appropriate file handling is in .npmignore now

Motivation

Reduces the size of our distributed package

Testing

• I tested this manually
• I added automated tests

used npm pack and diff'd the before and after to ensure that only the expected files were deleted

Documentation

Select one:

• I have added relevant documentation for my changes.
• This PR does not result in any developer-facing changes.