cve-bin-tool test: add invalid file test for package-lock.json files

In #3745, @imsahil007 added support for npm package-lock.json files, but since he added support for the type of file I'd been using for an invalid test, we need a new test for that:

We probably should still have some sort of invalid file test. Obviously the npm one we had won't work and you were correct to remove it, but maybe test it against something else that will show up as malformed?

Originally posted by @terriko in https://github.com/intel/cve-bin-tool/pull/3745#pullrequestreview-1839494443

This is probably a beginner-friendly issue.

Mar 13 '24 23:03 terriko

HI @terriko. Can I please take up this issue? This would help me prepare for my GSoC and it might also be a fruitful contribution other than just adding docstrings.

Mar 18 '24 04:03 mvp-2003

@mvp-2003 have fun! Let us know if you get stuck or have questions. Probably you just need to make an empty or intentionally invalid file with the expected name and try to load it for the test. You might want to look at the code that was removed in https://github.com/intel/cve-bin-tool/pull/3745 if you need an example.

Mar 18 '24 21:03 terriko

@terriko . looks like I am unable to finish this work. I apologize for the inconvenience. I lack knowledge and skills to work with this one. But thanks for giving me a chance. I'm sorry I couldn't be of much help.

Mar 29 '24 19:03 mvp-2003

Hi @terriko , I would like to work on this

Apr 14 '24 09:04 AstikSharma

@AstikSharma have fun and let us know if you have any questions!

Apr 15 '24 16:04 terriko