Investigate how to remove old deleted supplemental files from index on avalon-dev

[masaball]

Spinning this task off from #5892 for after 7.8 code is ready.

Supplemental Files that have been indexed and then deleted prior to implementation of the changes for #5892 are still going to be present in the index, which can cause errors and erroneous matches with the search service. This should only be a problem on Avalon-Dev, but we still need to come up with a strategy for cleaning the index.

Would doing a basic reindex clear out entries that no longer have a corresponding database object? Or do we need to do something more complex such as grabbing all the supplemental file ids from solr and directly checking the existence of each to determine if something should be removed from the index? Is there another approach that might be better?

Done Looks Like

• [ ] Investigate method
• [ ] Execute cleanup/deletion

[joncameron]

Can wait until 7.8 RC or full release.