Remove methods on NamespacesHelper not being used

What does this MR do and why?

While working on related code I noticed some methods in NamespacesHelper not being used, so this MR removes them

Screenshots or screen recordings

N/A

How to set up and validate locally

Pipelines passing should be enough validation

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.