Use
echo 'DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt || true";};' | sudo tee -a /etc/apt/apt.conf.d/70debconf
em vez de
sudo sh -c "echo 'DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-pr econfigure --apt || true";};' >> /etc/apt/apt.conf.d/70debconf"