Handle response objects of instance String for API errors

[kraju3]

Description

Due to unexpected errors such as Bad Gateway, the response object is of Instance string, while trying to fetch the provider_error we return a Ruby error of
undefined method fetch' for "Bad Gateway":String`

This PR addresses the type before parsing the provider_error property

License

I confirm that this contribution is made under the terms of the MIT license and that I have the authority necessary to make this contribution on behalf of its copyright owner.

[nickbair-nylas]

LGTM, worth adding a test case for this?

[AaronDDM]

Thanks Kiran! Could you add a test, ideally for a legitimate error that we're experiencing.

[kraju3]

@AaronDDM @nickbair-nylas I think there are some tests regarding this in http_client.spec file? Would you be able to sanity check if that is doing the same?

[nickbair-nylas]

@kraju3 the only test I see for #throw_error uses an error object (here). I think you could just copy this test and pass error as a string.

[kraju3]

Added a test for this change.

One of the github action is failing. I am not sure if it's related to this:
actions/runner-images#10636