release: ensure default sudo flavor is selected

pkg behaviour selects the non-default flavour, this trims
0,5GiB per cloudware image, by being explicit.

Approved by:	cperciva
Differential Revision:	https://reviews.freebsd.org/D48599
Sponsored by:	SkunkWerks, GmbH
PR:		284278
MFC after:	10 days

release/scripts/pkg-stage.sh

@@ -23,7 +23,7 @@ net/wifi-firmware-kmod@release
 ports-mgmt/pkg
 shells/bash
 shells/zsh
-security/sudo
+security/sudo@default
 sysutils/screen
 sysutils/seatd
 sysutils/tmux

release/tools/oracle.conf

@@ -19,7 +19,7 @@ export VM_EXTRA_PACKAGES="
     net/rsync
     panicmail
     security/ca_root_nss
-    security/sudo
+    security/sudo@default
     sysutils/firstboot-freebsd-update
     sysutils/firstboot-pkgs
     sysutils/panicmail