Child locations up to 1 level down are able to have a site

[amtypaldos]

Environment

• Nautobot version (Docker tag too if applicable): 1.4.5
• Python version: 3.8.10
• Database platform, version: Postgres 12.12
• Middleware(s):

Steps to Reproduce

1. Create a parent location and attach it to a site
2. Create a child of the above parent, and attach to a site

Expected Behavior

I expected to be unable to add a child location to a site as I am unable to do so with child locations two levels down, IE the child of a child location.

Observed Behavior

I was able to attach a child location to a site

[glennmatthews]

Based on discussion on Slack, it sounds like this may have happened because the "Floor" LocationType was changed to no longer have the "Building" LocationType as its parent. We probably need to disallow changing the parent of a LocationType that's already in use?