Bump UEFI disk image size for armhf to 3.5 GB LP:#1953609

Current impish builds fail with:
```
cp: error writing 'mountpoint/var/lib/snapd/snaps/snapd_14067.snap': No space left on device
cp: cannot create directory 'mountpoint/var/lib/snapd/ssl': No space left on device
```

This is a cherrypick backport from ubuntu/master

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.742.2) impish; urgency=medium
+
+  * Bump UEFI disk image size for armhf to 3.5 GB (LP: #1953609)
+    Current builds are failing because the disk size is not big enough.
+    This a backport from jammy and upstream livecd-rootfs:ubuntu/master.
+
+ -- Phil Roche <phil.roche@canonical.com>  Wed, 08 Dec 2021 11:24:18 +0000
+
 livecd-rootfs (2.742.1) impish; urgency=medium
 
   [ Thomas Bechtold ]

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

@@ -21,6 +21,11 @@ case ${PROJECT:-} in
         ;;
 esac
 
+if [ "$ARCH" = "armhf" ]; then
+    # bump to 3.5G (3584*1024**2); Since Impish and Jammy armhf need more then the default 2.2G
+    IMAGE_SIZE=3758096384
+fi
+
 # Change image size for preinstalled generic images & all preinstalled riscv64 images
 if [ -n "${SUBARCH:-}" ]; then
     if [ "${SUBARCH:-}" = "generic" ] || [ "$ARCH" = "riscv64" ]; then