api: fix unattended-upgrades for pkg not installed #2777

Job	Run time
Check secrets / Check secret	4s
Packaging (xenial)	4m 53s
Packaging (bionic)	5m 16s
Packaging (focal)	4m 45s
Packaging (jammy)	5m 20s
Packaging (lunar)	4m 35s
Packaging (mantic)	4m 47s
Integration (bionic, lxd, ubuntu-22.04)	1h 25m 26s
Integration (focal, lxd, ubuntu-22.04)	1h 15m 42s
Integration (jammy, lxd, ubuntu-22.04)	1h 10m 47s
Integration (lunar, lxd, ubuntu-22.04)	36m 28s
Integration (xenial, lxd, ubuntu-20.04)	1h 18m 8s
Integration (bionic, awspro, ubuntu-22.04)	35m 0s
Integration (bionic, gcppro, ubuntu-22.04)	40m 54s
Integration (bionic, awspro-fips, ubuntu-22.04)	15m 14s
	7h 47m 19s

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