Do not set `stacktrace` if there are no `frames`

[marandaneto]

e.g.:

{
  "exception": {
    "values": [
      {
        "type": "Error",
        "value": "TypeError: undefined is not a function, js engine: hermes",
        "stacktrace": {
          "frames": null
        },
        "mechanism": {
          "type": "generic",
          "synthetic": true,
          "handled": true
        }
      }
    ]
  }
}

The UI will show an error because of that.

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

---

"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀

[marandaneto]

Checking with the Web team if they can take it since the change is likely on the JS SDK.
Edit: Web Team will take it.

[AbhiPrasad]

This may be fixed with #4555, @timfish could you double check for us?

[timfish]

I will check!

I think I might have left it as it was while refactoring.

[timfish]

It looks like my changes can result in an empty array for stacktrace.frames.

The developer docs say that it should only be set if there is 1 or more frames so I'll fix this!

[timfish]

This PR contains a fix for this issue for node.js.

I'll do another PR to fix this for the browser SDK.