*.fbs files are incorrectly treated as binary, not plain text

Currently, this extension is being used as binary/image (MIME type: image/vnd.fastbidsheet) – This may be an update for pygit

Latest update from Atlassian 2023-04-15

We are treating this as a bug and have a fix underway. Once addressed, `.fbs` files will be rendered in plain text in source and diff views.