bait: cors issue when attempting to create a link in group settings

[zalberico]

• Go into group settings
• Enable invite links
• Add description
• Click save
• Observe it become saved, but no link gets shows
• Observe cors error in the console

[zalberico]

From @midsum-salrux:

to solve the cors issue I could 1. scry the metadata from the local reel state. we set it there when we poke the bait server, but it's theoretically possible for it to be out of sync. or 2. make a special "cors simple request" endpoint that's just plaintext and can only have certain headers. https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests

@philipcmonk with Nathan now helping on landscape/groups - can you take a look at this? I think fixing this is the last thing we need to cut release and be ready for hosting.