Adding unprocessedKeysForTable to BatchGetItem results object

[bmaizels]

Description

DynamoDB returns keys that could not be processed in a BatchGetItem result, however there was no way to get at these values
through the enhanced client. Inferring which keys were not processed by subtracting the results list from the inputs was not
sufficient because if any of the items were missing from the results, it would be impossible to know if they were not included in
the result set because they were not processed or if they were actually missing.

Motivation and Context

At least one customer has asked for this functionality. DynamoDbMapper provides this functionality by throwing an exception and providing the partial results and the unprocessed keys in that exception, so this is also a feature parity issue.

Testing

Unit tests.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have read the README document
• I have added tests to cover my changes
• All new and existing tests passed
• A short description of the change has been added to the CHANGELOG
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

100.0% Coverage
0.0% Duplication