When baking an Action on an object which has custom properties that come
from an addon or python script that isn't loaded, the baking would fail with:
```
TypeError: Cannot assign a 'dict' value to the existing 'hops' Group IDProperty
```
This comes from an addon that isn't present or loaded on a users machine.
The fix is to check for `IDProperty` and skip those.
Pull Request: https://projects.blender.org/blender/blender/pulls/129057
88f298f66f