The File Output node always has inputs of type Color regardless of the
type of the connected socket. This is because the socket type update
mechanism no longer works, so the default socket type persisted.
This is a regression due to 4a4916db45, where the RNA set function no
longer allows editing socket types for built-in nodes, and the File
Output node utilized the RNA set function. To fix this, we avoid the RNA
route and set the type directly.
This fix is related to #120175 and partially fixes it, though another
fix is still necessary.
Pull Request: https://projects.blender.org/blender/blender/pulls/120199
79ca9e5afe