Hide Project Repository Size Limit Field When Not In Admin Mode

What does this MR do and why?

If admin mode is enabled for the instance, and an admin is an owner of a project or group, the Repository size limit (MiB) field is visible on the project settings page, however saving a value silently fails. (If the admin is not an owner of the project or group, then the settings page returns a 404, so the line this MR changes in the view is a moot issue.)

This MR fixes the issue so that the field is not visible on the project settings page unless the admin has entered admin mode.

Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/424808

Screenshots or screen recordings

Before	After
Screen_Recording_2023-09-11_at_5.14.10_PM	Screen_Recording_2023-11-03_at_3.10.56_PM

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