Ignore ledger updates that contain commands rejected due to de-duplication.
Such updates should not be entered into the index database as a) they are redundant and can be confusing b) could open a DOS attack vector.

Pull Request Checklist

• Read and understand the contribution guidelines
• Include appropriate tests
• Set a descriptive title and thorough description
• Add a reference to the issue this PR will solve, if appropriate
• Add a line to the release notes, if appropriate
• Normal production system change, include purpose of change in description

NOTE: CI is not automatically run on non-members pull-requests for security
reasons. The reviewer will have to comment with /AzurePipelines run to
trigger the build.