Resolve "Not assign the MR author in security review"

What does this MR do and why?

I changed function "security_reviewer" in "security_review_ready.rb", when the MR author is a security reviewer, the function will not return this author's name.

Screenshots or screen recordings

How to set up and validate locally

Use GDK to validate locally.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• Modify function "security_reviewer" in "security_review_ready.rb", adjust its logic.
• Add test case for this new feature.
• Validate this new feature locally using GDK and debugging tools.
• Validate this new feature in staging env.

Closes #26 (closed)