feat(sogo): Upgrade from 5.11.2 to 5.12.0

[stephdl]

Brief description
We request to upgrade SOGo from 5.11.2 to 5.12.0
WHY: The current version (5.11.2) contains known bugs and lacks the latest security patches and improvements delivered upstream.

PURPOSE: Ensure the system benefits from upstream security fixes, stability improvements, and continued compatibility with official apps and integrations.

Proposed solution
Update the SOGo package in the repository to version 5.12.0, perform regression testing, and validate core functionality (e.g., file sync/share, user auth, app compatibility).

Alternative solutions
Remaining on the current version is not recommended due to unresolved issues and potential exposure to known vulnerabilities. Backporting individual patches is more complex and harder to maintain over time.

Additional context
SOGo includes security fixes, minor bugfixes, and improved compatibility with external apps.

SOGo is a key component of our collaboration suite, and keeping it up to date is crucial for security and functionality.

see also

https://github.com/Alinto/sogo/blob/master/CHANGELOG.md

[stephdl]

community verification asked to https://community.nethserver.org/t/sogo-5-12-0-needs-testers/25744

[stephdl]

QA

install an account provider and a mail server

• direct install, no issue expected
• upgrade from 5.11.2, no issue expected

[stephdl]

issue verified at https://community.nethserver.org/t/sogo-5-12-0-needs-testers/25744