Fix startup crash in Puma single mode

Merged Roy Zwambag requested to merge rz-puma-single-mode-148-patch into 14-8-stable-ee-patch-3

What does this MR do and why?

This MR fixes a crash if you start Puma in single mode, for full details see: !81983 (merged)

This MR is to pick it into the latest 14.8 patch as per the following steps: https://gitlab.com/gitlab-org/release/docs/blob/master/general/patch/process.md#process-for-developers

MR acceptance checklist

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

Edited by Roy Zwambag