Typo in AssessmentItemURI on AssessmentItem Domain Entity

It looks like this was introduced with the Data Standard 2.1 work almost 2 years ago, as part of work on DATASTD-158. When the new AssessmentItemURI was introduced, it was incorrectly implemented as "AsessmentItemURI" instead of "AssessmentItemURI". This was released with the Data Standard 3.0 release, but does not exist in the Data Standard 2.2 release.