Add Updated Augmented Dataset

[abenefield1]

We should update the augmented dataset in fiphde with the dataset that stops in April of 2024 instead of the current one, which went through later in 2024 - with gaps in the NHSN data due to the change in reporting API

[abenefield1]

See updated imputed summaries object that is ready to be folded into the package.

This has the imputed dataset with the augmentation process run through April 21, 2024 (prior to NHSN changes), and it also now includes the imputed ILINet data. I also added the prefix "unimputed." to columns in the dataset that reflect raw, unimputed data. We likely won't ever need these, but I kept them in case we had been using them for downstream or validation analyses that I was unaware of. But I added that prefix to help prevent us from using the wrong data column.