TIMX-234 Update aspace identifiers logic

[ghukill]

What does this PR do?

For ASpace records, any <unitid type="aspace_uri"> elements are skipped for consideration as TIMDEX record identifiers.

Helpful background context

It was discovered that some ASpace records after transformation contained multiple identifiers, of the same type, which was throwing errors in Bento. It looks as though ASpace records may have changed slightly and are exposing a new string for the element, which is the same as the OAI record identifier.

Before:

After:

How can a reviewer manually see the effects of these changes?

Run the following transform:

pipenv run transform -s aspace -i tests/fixtures/ead/ead_record_attribute_and_subfield_variations.xml -o output/aspace-ead-single-identifier.json

• observe that identifiers property only has a single value, despite two <unitid> elements present under <archdesc level="collection">

What are the relevant tickets?

https://mitlibraries.atlassian.net/browse/TIMX-234

Developer

• All new ENV is documented in README
• Stakeholder approval has been confirmed (or is not needed)

Code Reviewer

• The commit message is clear and follows our guidelines
  (not just this pull request message)
• There are appropriate tests covering any new functionality
• The documentation has been updated or is unnecessary
• The changes have been verified
• New dependencies are appropriate or there were no changes

Includes new or updated dependencies?

YES

[ehanson8]

Works as expected, can you just update the commit message title? It looks like it was accidentally omitted

[ghukill]

Works as expected, can you just update the commit message title? It looks like it was accidentally omitted

Thanks, nice catch. Updated.