Don't need `"carousel"` displayMode

[martinalong]

I think we can remove carousel from this enum:

displayMode?: "inline" | "fullscreen" | "pip" | "carousel";

• Seems unnecessary to specify since it doesn't require any different treatment from inline, assuming the arrow buttons are provided by the apps (which I think they should be, to avoid the complexity of communicating back and forth about whether we're at the start/end of the carousel)
• Not to mention:
  • Being a carousel is something that the app would decide, and not something that the host should be telling the app to be
  • Plus, you could be an inline carousel or a fullscreen carousel, so having them on the same property wouldn't capture the full range of states
  • And apps are probably either always a carousel or always not a carousel. It's not so much a "mode" as it as a "layout"

The one thing that gives me pause is that chatgpt apps spec does have a carousel option iirc. So maybe worth digging into why they have that, and what materially changes when that is specified?

[idosal]

Thanks @martinalong, you're right! It was added as a placeholder and then removed, but I must have inadvertently brought it back through copy and paste. It's now removed permanently (#56).