fix: arm flash-kernel removal from ubuntu-cpc project cloud images (LP: #2037074)

With the migration from linux-kvm to linux-virtual/generic for the mantic minimal
images we can now start building arm64 minimal cloud images.

When building initial test images we noticed that the flash-kernel package was being
installed. This is not required for EFI images.

This commit removes the flash-kernel package from the cloud images arm installs

The only images built using the livecd-rootfs ubuntu-cpc project for arm64 and armhf
which are not cloud images (which therefore do not require flash-kernel) are the
raspi images. raspi does require flash-kernel. But the raspi images use the
`ubuntu-server-raspi` task to install the flash-kernel. As such this non raspi
flash-kernel package install can be completely removed.

It also means that initramfs-tools and dracut-install are installed as these are dependencies
of flash-kernel package.

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (23.10.48) UNRELEASED; urgency=medium
+
+  * fix: arm64 flash-kernel removal from ubuntu-cpc project cloud images
+    (LP: #2037074)
+
+ -- Phil Roche <phil.roche@canonical.com>  Wed, 27 Sep 2023 11:34:05 +0100
+
 livecd-rootfs (23.10.47) mantic; urgency=medium
 
   [ Phil Roche ]

live-build/auto/config

@@ -1048,11 +1048,7 @@ case $PROJECT in
 			*+raspi)
 				add_task install ubuntu-server-raspi
 				;;
-			armhf*)
-				add_package install flash-kernel
-				;;
 			arm64*)
-				add_package install flash-kernel
 				if [ "${SUBARCH:-}" = "generic" ]; then
 					KERNEL_FLAVOURS=generic
 				fi