Update to Jackson 2.4.3

- Update pom to 2.4.3 from 2.4.2
- Enable the CBOR data header (aka tag) from the CBOR Generator to provide binary identification like the Smile format
- Check for the CBOR header and ensure that the data sent in represents a "major type" that is an object
- Cleans up `JsonVsCborTests` unused imports

Closes #7640
for other reviewers wondering where this change comes from, the first char is already checked earlier in this method