Hide dependency proxy for personal namespaces

What does this MR do and why?

It hides the dependency proxy block (within usage quotas > storage) from personal namespaces, so it shows only for groups.

Screenshots or screen recordings

before	after

How to set up and validate locally

1. Checkout master branch
2. Navigate to the user preferences > usage quotas > storage
3. Observe the dependency proxy block showing
4. Checkout 362694-hide-dependency-proxy-from-personal-namespaces branch
5. Navigate to the user preferences > usage quotas > storage
6. Observe there's no dependency proxy block

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.

Related to #362694