Remove --frozen flag for cargo-about (#26385)

This was added to support the nix build but accidentally broke our
bundling. I'll try to re-add it in a way that works for both in the
future.

Release Notes:

- N/A

script/generate-licenses-csv

@@ -17,7 +17,6 @@ echo "Generating cargo licenses"
 set -x
 cargo about generate \
     --fail \
-    --frozen \
     -c script/licenses/zed-licenses.toml \
     $TEMPLATE_FILE \
     | awk 'NR==1{print;next} NF{print | "sort"}' \