USN-8580-2: AccountsService vulnerabilities

USN-8580-1 fixed vulnerabilities in AccountsService. This update provides
the corresponding fixes for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS,
Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS.

Original advisory details:

It was discovered that the Ubuntu-specific SetLanguage patch to
AccountsService incorrectly handled dropping privileges. A local attacker
could use this issue to execute arbitrary commands as an administrator.
(CVE-2026-61897)

It was discovered that the Ubuntu-specific SetLanguage helpers for
AccountsService incorrectly handled parsing configuration files. A local
attacker could use this issue to execute arbitrary commands.
(CVE-2026-61898)