Cleanup new exception traceback

[KrishanBhasin]

I was browsing the latest changelog and stumbled across this tiny change, as per my most recent PRs

[mrocklin]

Thanks @KrishanBhasin . I'll admit to not knowing much about when this change would or would not be preferred. Can I ask you to explain the motivation a little?

[KrishanBhasin]

Hi @mrocklin, this is very similar to a previous PRs I have raised at #4042 and #4054

When the error is raised, the message will be slightly clearer for the user:

The above exception was the direct cause of the following exception:

instead of

During handling of the above exception, another exception occurred:

[mrocklin]

Thanks @KrishanBhasin !