Update subgroup creation page

What does this MR do and why?

Related to Eng: Update Subgroup creation page (#363420 - closed)

The goal of this issue is to update the subgroup creation experience. Currently, the same design is used for when a user creates a parent level group and a subgroup with the only change being that the subgroup page has a string attached to the URL in the location bar and includes an option for the URL path that the subgroup should have.

Screenshots or screen recordings

before	after

How to set up and validate locally

1. Sign in. Go to the groups page.
2. Create new internal group.
3. Go to this group page. Click New subgroup. Make sure subgroup creation page is opened.
4. Go back. Click New subgroup in header menu. Make sure subgroup creation page is opened.
5. Make sure dropdown contains only Owner and Maintainer groups.
6. Click import an existing group and make sure import page has Group URL with parent path.
7. Go back. Create new subgroup. Make sure in has Private visibility level.
8. Log out. Log in as admin. Go to Admin Area -> Groups.
9. Go to any subgroup edit page and make sure Group URL has parent path.

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.