Added counter and test for comments

[adamteddychang]

In this branch I :

• implemented the counter function to display the amount of comments are in the popup
• wrote a test to make sure the function returns the right result

[netlify[bot]]

✔️ Deploy Preview for heuristic-carson-d71dab ready!

🔨 Explore the source changes: 5218a64421fc66195b6add309d731ff7d80225cb

🔍 Inspect the deploy log: https://app.netlify.com/sites/heuristic-carson-d71dab/deploys/6196693ce21c190008dd194d

😎 Browse the preview: https://deploy-preview-34--heuristic-carson-d71dab.netlify.app

[taher-software]

Thank you for your determination. It's time to merge. Good luck !