0cf688401b
`paths_from_operator_properties` can return paths for both the explicit
operator `filepath` property as well as the `directory` content.
16129d6a attempted to fix this, but fails because one instance of a path
can be absolute and the other negative.
This patch makes sure to only compare absolute paths. Comparison uses
a separate list so that the final output can still mix absolute and
relative paths, but should only include each path once.
Pull Request: https://projects.blender.org/blender/blender/pulls/125608