[test]: add test case on package cgroup

[SamYuan1990]

add test case on package cgroup
remove duplicate function
fix a cache set logic when error happen on code logic

[github-actions]

🤖 SeineSailor

Here is a concise summary of the pull request changes:

Summary: This pull request enhances the cgroup package by adding test cases, refactoring functions, and improving error handling and efficiency. Key modifications include:

• Added three new tests for the Cache struct
• Refactored getContainerIDFromCache function for better error handling and efficiency
• Replaced extractPodContainerIDfromPath with extractPodContainerIDfromPathWithCgroup for enhanced cgroup functionality
• Fixed cache set logic when an error occurs

Impact: These changes focus on improving cGroup functionality and container management without altering exported function signatures, global data structures, or variables. However, the added test cases and cache set logic fix may affect the code's behavior.

Observations/Suggestions:

• The changes are well-contained within the cgroup package, making it easier to review and maintain.
• The added test cases will help ensure the reliability and stability of the cgroup package.
• It would be beneficial to consider adding more test cases to cover additional scenarios and edge cases.
• The refactored getContainerIDFromCache function and the replacement of extractPodContainerIDfromPath with extractPodContainerIDfromPathWithCgroup may require additional documentation to ensure clear understanding of the changes.

[sunya-ch]

LGTM!