feat: support unknown error types

[miguelvelezsa]

Description

Currently when decoding HTTP error, if the server returns an error that is not an rpc.StatusDetails, it will thrown an error about it instead of returning the real error. This is because it can't find the proto, the decoder is only using the error details loaded from status.json in https://github.com/googleapis/gax-nodejs/blob/main/gax/src/googleError.ts#L175). This PR will fix that.

Impact

Instead of throwing an error about the custom/unknown proto for the error, we are a going to convert it to a ResourceInfo error and put in the description the details from the custom/unknown error.

Testing

Added unit test for custom/unknown errors in this PR.

Additional Information

Any additional details that we should be aware of?

It seems RPC catch these kind of errors on https://github.com/googleapis/gax-nodejs/blob/main/gax/src/googleError.ts#L213, it is just ignoring but we need to show the info of the custom error. There is an internal bug about it, will work on that later.

Checklist

• [ Done] Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• [ Done] Ensure the tests and linter pass
• [ Done] Code coverage does not decrease
• Appropriate docs were updated
• [ Done] Appropriate comments were added, particularly in complex areas or places that require background
• No new warnings or issues will be generated from this change

Fixes #issue_number_goes_here 🦕 (no added, not sure if we can publish internal bugs here).