Fill in `flusurv` version history using local files from CDC contact

[nmdefries]

Following #1278, we have patched flusurv data through the present. However, the source doesn't track issues so the patched data is assigned to an issue date of 2025-11-03. We would like to patch in the version history, for completeness. A CDC contact previously said that they keep version history stored locally -- I believe @brookslogan is the relevant liaison.