style: format response tuple unpacking (extract helper)

[jnvw]

Summary

Refactors the response tuple unpacking logic in make_response into a small
private helper method to improve readability and maintainability.

No behavior changes are intended.

##Fixes #5907

Details

The existing tuple-unpacking logic inside make_response was moved into a
dedicated private helper method. This keeps the method shorter and easier to
reason about, without changing any runtime behavior.

Testing

• All existing tests pass.
• No new tests were added, as this change does not affect behavior.

Notes

This is an internal refactor only. No public API or documented behavior is
changed.