fix(deb): remove debian/compat — conflicts with debhelper-compat in Build-Depends

[levleontiev]

dpkg-buildpackage fails with:

dh: error: debhelper compat level specified both in debian/compat and via build-dependency on debhelper-compat

debian/compat (old method, value 13) and Build-Depends: debhelper-compat (= 13) (modern method) conflict.

Fix: delete debian/compat — the compat level is already declared in debian/control.

Seen in: https://github.com/fairvisor/edge/actions/runs/23906593464