F3 + I copies UUID

The bug

In previous versions, copying an entity with F3 + I removed the UUID from the NBT. With the migration from UUIDMost and UUIDLeast to UUID, this no longer happens, causing the generated command to fail if the original entity still exists.

How to reproduce

1. Spawn a mob
2. Look at it
3. Press F3 + I
4. Open a command block
5. Paste the command inside and activate it
→ Unable to summon entity (duplicate UUID)