Thanks to @demersus, it was discovered that the issue has to do with some irregularity around imports/exports. The solution that was found is to register
the format with Quill in the same file it is defined in. Additionally the format must be imported into the snow-with-payment
theme to ensure the format is register
ed.
After struggling for a few days to upgrade the link feature of Quill I've decided to write down my thoughts. To get help from other devs and keep a record of how to do this in the future.
The first step in learning how to add features to Quill is to understand Parchment, Quills internal representation for the DOM. Quill represents elements with its Blots while smaller changes to those elements (like setting an attribute) can be done with Attributors.