fix: error handling of non-standard Error instances

[aradbar]

Fixes #403

Description:
We encountered the following error from the error handler:
TypeError: Cannot set property message of which has only a getter
Whenever anything throws an error that for some reason doesn't have a settable message attribute.

Type of change:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Why is this change required?:
The error TypeError: Cannot set property message of which has only a getter hides the original error

Code changes:

---

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[github-actions]

CLA Assistant Lite bot CLA CHECK All Contributors have signed the CLA

[aradbar]

I have read the CLA Document and I hereby sign the CLA

[nicholasgriffintn]

Thanks! I'll take a look through this asap!

[codeclimate]

Code Climate has analyzed commit b76cb74 and detected 1 issue on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	1

The test coverage on the diff in this pull request is 100.0% (80% is the threshold).

This pull request will bring the total coverage in the repository to 96.9% (1.8% change).

View more on Code Climate.