Switch GitHub Copilot Chat from o1-mini to o3-mini

[notpeter]

When you try to send a message to o1-mini with copilot chat because o1-mini is no longer a supported model this error appears:

Failed to connect to API: 400 Bad Request
{"error":
  "message": "The requested model is not supported.",
  "param" "model",
  "code":"model _not_supported",
  "type": "invalid_request_error"
}}" 

• Supercedes: Update Copilot Chat o1-mini to o3-mini #24066

Thanks @SkywardSyntax.

Release Notes:

• Add Copilot Chat support for o3-mini and remove support for o1-mini (thanks @SkywardSyntax)

[notpeter]

I have not seen an announcement explicitly stating o3-mini will be replacing o1-mini entirely, so we may have to restore o1-mini Copilot Chat function in the near future.

I think this may be incorrect and that the availability / unavailability of o1-mini and o3-mini is transitory. I was original able to access o3-mini but not o1-mini; then briefly neither. I am now able to access only o3-mini. If you are having trouble accessing o3-mini I recommend you open VSCode, open Copilot Chat, attempt to use it there first and confirm it is working before trying again in Zed.

Note if you are using Copilot for Business / Enterprise this may require your GitHub Organization admin to opt-in to support these models.