Remove default values from publisher entries when pre-processing

[eporter23]

This ticket follows work to identify why some types of publications are receiving the default "Emory University Libraries" value when an actual publisher entry is present in the descMetadata MODS XML. See initial findings in #565. This seems to be affecting certain non-Article types of publications.

After discussion, we determined the best resolution would be to remove that logic from the processing step.

Desired outcomes:
If a mods:publisher is present using the expected xpath, use that value in the publisher field
If a mods:publisher is not found using the expected xpath, leave publisher blank in the CSV file.

[eporter23]

For testing, we can generate a new batch of exports and a CSV file in order to see the changes.

[bwatson78]

PR made: #629

[bwatson78]

Per https://eulcoreservices.slack.com/archives/GA9R6ADNH/p1731683642304159?thread_ts=1731682515.034879&cid=GA9R6ADNH, I am reverting this change

[bwatson78]

#644