CV indexing issue in TMLE

[nhejazi]

On branch tmle, the EIF is extracted from cross_validate to begin the TMLE update at https://github.com/nhejazi/medoutcon/blob/tmle/R/estimate.R#L466. At this point, the elements of this list are in the same relative order, but this does not match the order of the data. Thus, any fluctuation updates or scores computed after this point will be based on mismatched observations. To fix this, code from Lrnr_cv can be adopted: https://github.com/tlverse/sl3/blob/timeseries-overhaul/R/Lrnr_cv.R#L351