alternativeIdentifierType attribute in DataCite XML was always set to :unav for otherId fields from citation metadatablock

[qqmyers]

What this PR does / why we need it: Per discussion related to #11916 in https://docs.google.com/spreadsheets/d/1yvpIgD5tTst2Momu3RnzihmeEMvYH-TgfKjF7cdmJwg/edit?gid=0#gid=0, the processing of the Other Identifier fields to create the DataCite XML export/submission to DataCite has a bug that causes the identifier type to be set to :unav even when it is available (the otherIdAgency field has a value). This PR fixes that issue.

Which issue(s) this PR closes:

• Closes #

Special notes for your reviewer:

Suggestions on how to test this: Add entries for the two Other Identifier fields (otherIdAgency, otherIdValue) and verify that the DataCite XML output includes a section like

<alternateIdentifiers>
<alternateIdentifier alternateIdentifierType="{otherIdAgency}">{otherIdValue}</alternateIdentifier>
</alternateIdentifiers>

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

Is there a release notes update needed for this change?: fairly minor issue to include

Additional documentation:

[coveralls]

coverage: 24.23% (-0.001%) from 24.231%
when pulling ec56845 on GlobalDataverseCommunityConsortium:otherIdentifierBug
into 70b6e26 on IQSS:develop.