Hide settings search from project storage usage

What does this MR do and why?

It hides the settings search bar from the project storage usage page.

The MR doesn't have a changelog nor documentation update because the change is still behind a feature flag.

Related to #341830

Screenshots or screen recordings

before	after

How to set up and validate locally

1. Enable project_storage_ui feature flag in rails console: Feature.enable(:project_storage_ui)
2. Visit a project, then go to Settings -> Usage Quotas
3. The page shouldn't have a search bar at the top

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.