This verification service is provided by deepin-elf-verify, and it can be easily disabled with a simple text edit.

cd /usr/share/deepin-elf-verify/
cat mode

It should report a value of 1, indicating that the enforced package signature verification is ON.

sed -i 's/1/0/g' mode 
systemctl restart deepin-elf-verify.service

By changing it to 0 and restarting the service, we have successfully disabled it.