[Bug]: device_info_plus on Linux keeps the single quotes from os-release (Gentoo) #4011

Platform: Linux · Plugin: device_info_plus · Version: 13.3.0 (also current main)

Steps to reproduce

1. Run an app on Gentoo (or any distro whose /etc/os-release uses single quotes). Gentoo's file now looks like this:

   NAME='Gentoo'
   ID='gentoo'
   PRETTY_NAME='Gentoo Linux'
   VERSION='2.18'
   VERSION_ID='2.18'
   

2. Call DeviceInfoPlugin().linuxInfo.

Expected: id == 'gentoo', name == 'Gentoo', prettyName == 'Gentoo Linux'.

Actual: the quotes are kept: id == "'gentoo'", name == "'Gentoo'", prettyName == "'Gentoo Linux'", so a check like info.id == 'gentoo' is false.

Cause: _Unquote.unquote() in device_info_plus_linux.dart strips only double quotes. os-release(5) allows values in double or single quotes, and Gentoo switched to single quotes this year (Ansible and Facter both had to patch their parsers for it).