fix: Set the required debconf settings to allow for non interactive grub updates in cloud images (LP: #2054103)

As part of addressing LP: #2054103 [1] an update to grub-pc added a feature to be able to ensure that grub-pc
installation can happen noninteractively on cloud images.

This change is equivalent to running

```
debconf-set-selections grub-pc grub-efi/cloud_style_installation boolean true
debconf-set-selections grub-pc grub-pc/cloud_style_installation boolean true
```

These were introduced optionally to determine the install device using
`grub-probe` dynamically instead of having to fill the `grub-pc/install-devices`
debconf entry.

[1] https://bugs.launchpad.net/cloud-images/+bug/2054103

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (24.04.43) UNRELEASED; urgency=medium
+
+  * Set the required debconf settings to allow for noninteractive
+    grub updates in cloud images (LP: #2054103)
+
+ -- Philip Roche <phil.roche@canonical.com>  Fri, 23 Feb 2024 13:54:57 +0000
+ 
 livecd-rootfs (24.04.42) noble; urgency=medium
 
   [ Sean Davis ]

live-build/ubuntu-cpc/hooks.d/base/disk-image-uefi.binary

@@ -130,6 +130,9 @@ install_grub() {
         amd64)
             chroot mountpoint apt-get install -qqy ${package_install_recommends_option} grub-pc shim-signed
             efi_target=x86_64-efi
+            # set the required debconf settings to allow for non interactive grub updates in cloud images LP: #2054103
+            echo "grub-pc grub-efi/cloud_style_installation boolean true" | chroot mountpoint debconf-set-selections
+            echo "grub-pc grub-pc/cloud_style_installation boolean true" | chroot mountpoint debconf-set-selections
             ;;
         riscv64)
             chroot mountpoint apt-get install -qqy ${package_install_recommends_option} u-boot-menu grub-efi-riscv64