### Tested versions 4.7.2 ### System information N/A ### Issue description when using the `@export_custom` annotation with `PROPERTY_HINT_TYPE_STRING` on a variable typed as string, clicking on the variable in the inspector causes the engine to crash. ### Steps to reproduce - create a script - type `@export_custom(PROPERTY_HINT_TYPE_STRING, x) var any_name: String` : x -> `hint_string` ~~can be anything, including empty~~ any string that isn't a recognised class. - click on the assignment spot in the inspector crash insues. ### Minimal reproduction project (MRP) N/A