Make error context a non-enumerable property to avoid serialization errors

[msmithgu]

Error contexts can contain complex objects with circular references. By making the error context property non-enumerable, it's still accessible directly but won't be included automatically if someone tries to serialize the exception for logging.

[msmithgu]

This may also address what #46 is trying to address: that is making the error context not writable.

[enicholson]

@othiym23 any comments on this one? We've found this really helpful preventing crashes in our service which frequently serializes error objects (for responses, logging, etc).

Thanks!

[enicholson]

@msmithgu there is one more place where the error@context is assigned on line 85: https://github.com/MyPureCloud/node-continuation-local-storage/blob/efcfebb0151fb92728e82b867b246f4f0af31c4b/context.js#L85

That should have the same behavior...

[Qard]

Thanks! I'll add some tests for this and get it merged. 😸

[wanglihui]

this fixed my problem! 3q