Include underlying err.reason as err.cause for MongooseServerSelectionError

[alexbevi]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

The atlasMessage that overwrites the error message can make it difficult to actually troubleshoot certain errors.

Can we include the original err.reason as the Error.cause?

Motivation

No response

Example

No response

[baileympearson]

@vkarpov15 Thanks for merging this improvement quickly - would you be open to a PR that instead attaches the entire underlying error as the cause? Providing an error as the cause gives users the reason and the full stack trace to the underlying driver error.

[vkarpov15]

@baileympearson sure, feel free to put in that PR