fix: uncaught DynamoDB exception

[pivstone]

Description

• DynamoDB have rate limit, when we hit read cap, AWS SDK Client will throw an exception, but in the implementation it was using callback. So the callback function will never be called.
• So the value will never return to end of client.
• An uncaught exception may crash backend application in some cases

Requirements

• I have added test coverage for new or changed functionality
• I have followed the repository's pull request submission guidelines
• I have validated my changes against all supported platform versions
  • the fix is aiming for node server sdk with dynamodb, should be compatible

Related issues

N/A

Describe the solution you've provided

• try catch the error and pass undefined to callback function

Describe alternatives you've considered

• 1. don't use callback, this is a common and typical issue with mixing callback, promise and async/await
• 2. to have a error type for callback. usually callback have two parameters:

callback: (value, error) -> void

Additional note

• to cover this kind issue, better to have a integration test, we are using Nock to re-produce this issue in our internal, but LD isn't using such a tool, so we didn't at test in PR.

[kinyoklion]

@pivstone Thank you for the contribution.