Group member should not be allowed to make new menus with just 'Manage menu items' permission

Problem/Motivation

A group member that does not have the "Manage menus" permission can still create Group Menus, as long as they have "Manage menu items" permission assigned to them. The permission "Manage menu items" should only be for managing links in a group menu.

Steps to reproduce

Refer to attached screenshots.

1. Add a test user in a Group
2. Assign only 'Manage menu items' permission to test user
3. Assign appropriate 'Entity: Add content item entities' permission(s) to test user
4. Log in as test user, go to a Group > click Nodes tab > click Add new content
5. Select a content type
6. Navigate to the breadcrumbs, click on Add new content
7. New Group menu will be shown
8. Click and and test user will be able to create a new Group menu

Proposed resolution

Group permission "Manage menu items" should only be used for managing (create, update, delete) group menus.

Remaining tasks

Make a patch.