Fix performance problem with Projects#new page

What does this MR do and why?

Contributes to #425166 (closed)

Problem

We have N+1 query problem that leads to thousands of requests on https://gitlab.com/projects/new.

Solution

Preload necessary tables for project query to prevent N+1 problem.

Screenshots or screen recordings

Before

After

How to set up and validate locally

1. Visit http://127.0.0.1:3000/projects/new

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.