is-clean-unzip fails to recognize zipfile as clean

[razzius]

For example the zipfile here: https://github.com/BrianHenryIE/bh-wc-checkout-rate-limiter/releases

has a toplevel folder but it lists 162 files so the check for only 1 file fails.

Repro:

$ cd (mktemp -d)
tmp.RZvSGzez $ wget https://github.com/BrianHenryIE/bh-wc-checkout-rate-limiter/releases/download/1.3.1/bh-wc-checkout-rate-limiter.1.3.1.zip
tmp.RZvSGzez $ is-clean-zip bh-wc-checkout-rate-limiter.1.3.1.zip 
tmp.RZvSGzez $ echo $status
1