Fusion: fix unwanted change to field name in Settings

[kalisp]

Changelog Description

It should be image_format but in previous refactoring PR it fell back to original output_formats which caused enum not to show up and propagate into plugin.

Additional info

Previously:

Now:

In images:

Testing notes:

1. Update Settings - set output format
2. create image and render instances in fusion, watch that change in Setting propagated into creators