fix: throw empty error in extractAllToAsync on operation done

[Autokaka]

When extraction for each fileEntry is done, on should callback first before deleting the entry since the implementation of done function will always check and throw if current fileEntries is empty.

[EnigmaJJ]

const done = () => { if (fileEntries.size === 0) { callback(); } };
I found callback is not be called because fileEntries.size is never zero?

[jakebailey]

This caused a regression: #475

[komyg]

I had the same problem. The done callback is never called.

[bimalkjha]

So, the check for fileEntries.size should be removed if intension is to call callback first before fileEntries.delete(entry);. i.e. just replace done(); with callback();. Thanks.