Do not use cached column list for namespaces

What does this MR do and why?

Do not use cached column list for namespaces

Many other queries for namespaces table do not use cached column list, so we make this one place consistent with the rest.

This fixes the error that caused gitlab-com/gl-infra/production#14469 (closed), so that we do not have to revert db/migrate/20230516044606_add_organization_id_to_namespace.rb for self-managed

See gitlab-com/gl-infra/production#14469 (comment 1397860588), !80421 (comment 856860812), and gitlab-com/gl-infra/production#14470 (closed)

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Queries:

• count_master.sql
• count_branch.sql
• members_master.sql
• members_branch.sql

How to set up and validate locally

Follow gitlab-com/gl-infra/production#14470 (comment 1402753645) - the difference is that there should be no 500

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.