MDEV-39126: Feedback plugin to use /etc/os-release

[itzanway]

Description

This PR resolves MDEV-39126 by updating the feedback plugin to use /etc/os-release instead of the obsolete /etc/lsb-release for OS discovery.

As noted in the issue, /etc/lsb-release is outdated (Debian now isolates it to its own package), while /etc/os-release is the modern, portable standard across Linux distributions.

Implementation Details

• Primary Check: Modified prepare_linux_info() in plugin/feedback/utils.cc to attempt opening /etc/os-release first.
• Parsing: Added logic to parse the PRETTY_NAME= field and safely strip the wrapping double quotes to extract a clean, human-readable distribution name.
• Fallback Maintained: To ensure backwards compatibility with older systems that may not have /etc/os-release, the original /etc/lsb-release and wildcard mask (/etc/*-release) checks have been retained as fallbacks.

Testing

• Confirmed the C++ syntax and parsing logic.
• Relying on Buildbot CI to verify cross-platform compilation and ensure no regressions on older build environments.

[gkodinov]

Thank you for your contribution! This is a preliminary review.

First of all: please squash your two commits into a single one and add a commit message that's complaint to MariaDB condig standards (you can find the .md file with these in the repository).

Secondly (and optionally, at least for the preliminary review): would you please consider implementing a test for this?

I'd give it a day or two and go about it by checking in mtr if I'm running on a suitable platform (otherwise skip). Then I'd inspect the contents of the https://mariadb.com/docs/server/reference/system-tables/information-schema/information-schema-tables/information-schema-feedback-table and try to find the info from os_release there.