fix(data-grid): prevents null or undefined break max content length calculation

[NOMADE55]

What does this PR do?

• Fixes issue ScaleDataGrid not displayed when there is null value in rows prop #2376
• Prevents null or undefined values from breaking data-grid component.

Quick summary

Data Grid component calculates the longest row. For this it relies on the .toString() method. And then chains it to length.
Both null and undefined lack the former one, and will break the component after invoking the method.

What has been done

• Add to 0 as default-
• optional chaining to prevent these values from breaking the component.

Some Observations

• This is my first PR here 👋🏻 so if I'm missing something let me know.
• I'm still figuring lerna and this monorepo out, so any observations are welcome.
• Tested locally in a mock project.

[netlify]

✅ Deploy Preview for marvelous-moxie-a6e2fe ready!

Name	Link
🔨 Latest commit	8ce3a45
🔍 Latest deploy log	https://app.netlify.com/sites/marvelous-moxie-a6e2fe/deploys/6763a86cf40df400089a5922
😎 Deploy Preview	https://deploy-preview-2377--marvelous-moxie-a6e2fe.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.