`ppp-multilink` replaces `ppp`, but imagebuilder still wants to install both, resulting in conflict.

Ahoj,

I want to run an attended sysupgrade run (via LuCI), and I have installed the package ppp-multilink. ppp-multilink can replace ppp, but the image generator seems to wanting to install both ppp and ppp-multilink, resulting in a conflict:

[...]
Collected errors:
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/etc/ppp/chap-secrets
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/etc/ppp/filter
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/etc/ppp/options
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/lib/netifd/ppp-down
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/lib/netifd/ppp-up
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/lib/netifd/ppp6-up
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/lib/netifd/proto/ppp.sh
	But that file is already provided by package  * ppp
 * check_data_file_clashes: Package ppp-multilink wants to install file /builder/build_dir/target-mipsel_24kc_musl/root-ramips/usr/sbin/pppd
	But that file is already provided by package  * ppp
 * opkg_install_cmd: Cannot install package ppp-multilink.
[...]

Request to the sysupgrade server:

{
    "url": "https://sysupgrade.openwrt.org",
    "revision": "r23389-5deed175a5",
    "advanced_mode": "1",
    "sha256_unsigned": "",
    "branch": "23.05",
    "efi": null,
    "request_hash": "418e536eaac26c8dfb5b301a399e8e65",
    "profile": "vocore,vocore2",
    "target": "ramips/mt76x8",
    "version": "23.05.0-rc3",
    "packages": [
        "auc",
        "base-files",
        "busybox",
        "ca-bundle",
        "cgi-io",
        "comgt-ncm",
        "dnsmasq",
        "dropbear",
        "f2fsck",
        "firewall4",
        "fstools",
        "fwtool",
        "getrandom",
        "gpioctl-sysfs",
        "gpiod-tools",
        "hostapd-common",
        "ip6tables-nft",
        "iptables-nft",
        "iw-full",
        "iwinfo",
        "jansson",
        "jshn",
        "jsonfilter",
        "kernel",
        "kmod-cfg80211",
        "kmod-crypto-acompress",
        "kmod-crypto-aead",
        "kmod-crypto-ccm",
        "kmod-crypto-cmac",
        "kmod-crypto-crc32c",
        "kmod-crypto-ctr",
        "kmod-crypto-gcm",
        "kmod-crypto-gf128",
        "kmod-crypto-ghash",
        "kmod-crypto-hash",
        "kmod-crypto-hmac",
        "kmod-crypto-manager",
        "kmod-crypto-null",
        "kmod-crypto-rng",
        "kmod-crypto-seqiv",
        "kmod-crypto-sha512",
        "kmod-fs-f2fs",
        "kmod-gpio-beeper",
        "kmod-gpio-button-hotplug",
        "kmod-i2c-gpio",
        "kmod-leds-gpio",
        "kmod-ledtrig-activity",
        "kmod-ledtrig-audio",
        "kmod-ledtrig-gpio",
        "kmod-ledtrig-oneshot",
        "kmod-ledtrig-pattern",
        "kmod-ledtrig-transient",
        "kmod-ledtrig-tty",
        "kmod-lib-crc-ccitt",
        "kmod-lib-crc32c",
        "kmod-lib-lzo",
        "kmod-mac80211",
        "kmod-macvlan",
        "kmod-mdio-gpio",
        "kmod-mhi-wwan-mbim",
        "kmod-mmc-spi",
        "kmod-mt76-core",
        "kmod-mt7603",
        "kmod-mux-gpio",
        "kmod-nf-conntrack",
        "kmod-nf-conntrack6",
        "kmod-nf-flow",
        "kmod-nf-log",
        "kmod-nf-log6",
        "kmod-nf-nat",
        "kmod-nf-reject",
        "kmod-nf-reject6",
        "kmod-nfnetlink",
        "kmod-nft-core",
        "kmod-nft-fib",
        "kmod-nft-nat",
        "kmod-nft-offload",
        "kmod-ovpn-dco",
        "kmod-ppp",
        "kmod-pppoe",
        "kmod-pppox",
        "kmod-sdhci-mt7620",
        "kmod-slhc",
        "kmod-spi-gpio",
        "kmod-usb-ledtrig-usbport",
        "kmod-usb-net-cdc-eem",
        "kmod-usb-net-cdc-ether",
        "kmod-usb-net-cdc-ncm",
        "kmod-usb-net-cdc-subset",
        "kmod-usb-net-huawei-cdc-ncm",
        "kmod-usb-net-qmi-wwan",
        "kmod-usb-ohci",
        "kmod-usb-serial",
        "kmod-usb-serial-ftdi",
        "kmod-usb-serial-option",
        "kmod-usb-serial-simple",
        "kmod-usb-serial-wwan",
        "kmod-usb-storage",
        "kmod-usb-storage-extras",
        "kmod-usb-storage-uas",
        "kmod-usb-wdm",
        "kmod-usb2",
        "libblobmsg-json",
        "libiwinfo",
        "libiwinfo-data",
        "libjson-c",
        "libjson-script",
        "liblucihttp",
        "liblucihttp-ucode",
        "libmnl",
        "libnftnl",
        "libnl-tiny",
        "libubox",
        "libubus",
        "libuci",
        "libuclient",
        "libucode",
        "libustream-wolfssl",
        "logd",
        "luci",
        "luci-app-attendedsysupgrade",
        "luci-app-firewall",
        "luci-app-ledtrig-rssi",
        "luci-app-ledtrig-switch",
        "luci-app-ledtrig-usbport",
        "luci-app-openvpn",
        "luci-app-opkg",
        "luci-app-sqm",
        "luci-app-uhttpd",
        "luci-app-watchcat",
        "luci-base",
        "luci-light",
        "luci-mod-admin-full",
        "luci-mod-network",
        "luci-mod-status",
        "luci-mod-system",
        "luci-proto-3g",
        "luci-proto-ipv6",
        "luci-proto-mbim",
        "luci-proto-modemmanager",
        "luci-proto-ncm",
        "luci-proto-ppp",
        "luci-proto-qmi",
        "luci-proto-wireguard",
        "luci-theme-bootstrap",
        "mbim-utils",
        "mmc-utils",
        "mtd",
        "netifd",
        "nftables-json",
        "odhcp6c",
        "odhcpd-ipv6only",
        "openvpn-mbedtls",
        "openwrt-keyring",
        "opkg",
        "picocom",
        "ppp-mod-pppoe",
        "ppp-multilink",
        "procd",
        "procd-seccomp",
        "procd-ujail",
        "px5g-wolfssl",
        "rpcd",
        "rpcd-mod-file",
        "rpcd-mod-iwinfo",
        "rpcd-mod-luci",
        "rpcd-mod-rrdns",
        "rpcd-mod-ucode",
        "spi-tools",
        "spidev-test",
        "swconfig",
        "tc-full",
        "ubox",
        "ubus",
        "ubusd",
        "uci",
        "uclient-fetch",
        "ucode",
        "ucode-mod-fs",
        "ucode-mod-html",
        "ucode-mod-math",
        "ucode-mod-ubus",
        "ucode-mod-uci",
        "udns-dnsget",
        "uhttpd",
        "uhttpd-mod-ubus",
        "urandom-seed",
        "urngd",
        "usb-modeswitch",
        "usbutils",
        "usign",
        "wireless-regdb",
        "wpad-wolfssl",
        "wwan"
    ],
    "diff_packages": true,
    "filesystem": "squashfs",
    "client": "luci/git-23.132.65998-fa9fb2f"
}

Regards!

Start by reproducing the attended sysupgrade request for the vocore,vocore2 profile on the 23.05 branch with both ppp-multilink and the generated package set. Trace how ASU builds and resolves the package list, then verify that the completed image no longer attempts to install conflicting ppp and ppp-multilink packages.