It’s not possible. (A packaged version of your island is what exists when you publish it, and currently I’m not aware of any way to get any info out of a published island)
Bringing up ‘windows recovery’ is good though. When you delete files your hard drive doesn’t erase the data, it just marks the area where the data is as ‘ok to overwrite’. (I guess this saves hard-drive life by reducing read-write cycles) soooo… if you’re really desperate there could be a path forward for recovery with one of those type of restoration tools.