Cleaning Assets leaves Enemy/Civilian Element units unloaded

[RexTheWho]

Describe the bug

In the Assets panel if you unload unused units characters are also unloaded and leads to crashing or missing characters when playtesting.

Steps to reproduce the issue

Character/Unit spawning elements may need to be checked when cleaning Assets to avoid unloading units that arent spawned by still required.

Log file

No response

Minimal reproduction

No response