Oh yeah! Went down a rabbit hole this morning. They are just kind of gone after the update for some reason. I was able to find them in the old location being '/Library/Audio/Apple Loops/Apple'
The files you want are in the "JamPack" group of folders as well as "Apple Loops for Garage Band"

I recommend merging the old files with the new. You can copy them into '/Users/<user_name>/Music/Logic Pro Library.bundle/Apple Loops/z_Legacy' When it asks about overriding existing files, I selected 'Skip' since some were duplicates (hence why some are showing in the browser, but not all).
Then when in the Loop Browser in Logic, select the Sound Packs option at the top, and all the way at the bottom is "Reindex All Loops" let it chew through the files, and they should show up again as normal. I went from ~27k loops to 32k (not counting custom ones).

Hope this helps!