Removes feature flag `ci_increase_includes_to_250`

What does this MR do and why?

Removes the experimental feature flag:

ci_increase_includes_to_250: functionality will not be worked on soon until a thorough performance analysis has been made.

and removes the code associated with it.

MR acceptance checklist

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

• I have evaluated the MR acceptance checklist for this MR.