ci: improve container testing stability and dependencies

[mjun0812]

• Move "Install System Dependencies (Container)" step to an earlier position.
• Add 'git' to the list of installed system dependencies.
• Make system information commands (df, cpuinfo, os-release, free) more robust by adding '|| true'.
• Replace 'lscpu' with 'cat /proc/cpuinfo' for better compatibility.

This pull request updates the system dependency installation and container information steps in the .github/workflows/_test-container.yml workflow. The main changes focus on improving compatibility and reliability of the CI setup for container-based tests.

Container setup improvements:

• The "Install System Dependencies (Container)" step now installs additional packages (sudo and git) for all supported package managers, ensuring a consistent environment across different Linux distributions.
• The commands in the "Show Container Information" step are made more robust by appending || true, preventing the workflow from failing if any command is unavailable in the container. Additionally, lscpu is replaced with cat /proc/cpuinfo for broader compatibility.

Workflow cleanup:

• The duplicate "Install System Dependencies (Container)" step at the end of the job is removed, consolidating package installation logic into a single, more complete step.