bug_2931: resolving numpy integer check and adding test

[MCBoarder289]

Thanks to @emmanuelle for directing where this fix would live and even some code to make it work!

I also looked for similar checks and found some in subplots.py, but by that time this check must have already passed since I'm using subplots in my unit test.

Also considered if we should leverage what is in packages\python\plotly\_plotly_utils\basevalidators.py for coercion, but opted for this simple import try. Open to all feedback on how to improve this PR!

Code PR

• I have read through the contributing notes and understand the structure of the package. In particular, if my PR modifies code of plotly.graph_objects, my modifications concern the codegen files and not generated files.
• I have added tests (if submitting a new feature or correcting a bug) or
  modified existing tests.
• For a new feature, I have added documentation examples in an existing or
  new tutorial notebook (please see the doc checklist as well).
• I have added a CHANGELOG entry if fixing/changing/adding anything substantial.

[nicolaskruchten]

Thanks! I'm sorry we haven't been communicative on your PRs... we've been a bit backlogged these days, but I'll try to get them merged in for our upcoming 4.8 release on Tuesday :)

[MCBoarder289]

You’re welcome, just glad I could help contribute! Looking forward to hearing back any feedback you all have.

[emmanuelle]

Thanks a lot @MCBoarder289 ! Sorry for the time it took to review, I'll try to do better for your next patch ;-). Thanks again.