Refuse to set the RNA property `AnimData.animation_binding_handle` when `AnimData.animation` is nil. When in a hypothetical future `AnimData.animation` would be set, the binding handle would be ignored anyway, as it's only meaningful within the context of a known animation. Refusing to set the binding handle in cases where it is known to be meaningless may help to find bugs in Python scripts. Pull Request: https://projects.blender.org/blender/blender/pulls/121268