Decrease ABC threshold to 55.25

What does this MR do?

• Refactor lib/github/import.rb:223:5 with extracting method
• Decrease ABC threshold to 55.25

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

It's third step for #28202 (moved)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

#28202 (moved)

/cc @rymai @markglenfletcher @grzesiek

Possible labels: Community Contribution backstage Edge