OG and Favicons are uploaded as private files

**Describe the bug**
When uploaded through the builder's interface, the OG image and Favicons are saved as private files.

I think these should be public, the favicon doesn't render for guests users (asserted this though manual check)

Have not seen abnormalities with the OG image, but it makes sense to keep that as public as well

**Expected behavior**
Favicons and OG images are public by default

Start by reproducing an OG image and favicon upload through the builder's interface, then trace where their file visibility is assigned. Done means both asset types are public by default and a guest can render the favicon; verify the behavior for both assets after upload.

Written by the indexing model from the issue text.