Instance levels dont load custom packages in editor

[RexTheWho]

Describe the bug

When loading into an instance custom packages do not load, Only workaround seems to be opening a real level and loading the package on that one then change to the instance level and then you can place units.

If you have placed units in the instance that are from the custom package you will have a popup saying those units are not loaded and cant be loaded automatically because theyre custom.

Steps to reproduce the issue

• Make fully new custom units (can just be a renamed existing unit using existing assets)
• Make a custom package (eg. packages/my_big_package.xml)
• Make instance level
• Load custom package into instance level
• Attempt to place custom units (they will not be listed in the spawn menu)

Log file

No response

Minimal reproduction

No response

[RexTheWho]

Minimal Repro.
Load into the instance BRInstancePackagesInstance
You should be greeted with units not being loaded despite being loaded.

BRInstancePackages.zip