nvidia-driver-535 has unwanted dkms dependency

[Jack Howarth]

Prior nvidia-driver packages allowed for installation of the signed kernel modules in linux-modules-6.2.0-*-generic packages and the signatures for secure boot to access in linux-signatures-nvidia-6.2.0-*-generic when installed from the Additional Drivers panel in Software & Updates. The nvidia-driver-535 added a dependency on dkms which undoes this prior behavior. This represents a regression on how the nvidia drivers are handled for Ubuntu systems using secure boot. Especially as the automatation for manually signing locally built nvidia kernel modules seems to have been removed in 23.04.