partition-gpt: Work around debos regression

This fixes

2024/08/15 15:16:43 Action recipe failed at stage Run, error: esp mount failed: no such device

when building the amd64 image on current trixie

See https://gitlab.com/kalilinux/build-scripts/kali-vm/-/commit/d14cc43990e7d86e1d6b02bbbb226b09d380944a