assistant: Ensure that zed provider is listed as first option (#15496)

Release Notes:

- N/A

crates/assistant/src/model_selector.rs

@@ -60,6 +60,7 @@ impl<T: PopoverTrigger> RenderOnce for ModelSelector<T> {
                 for (index, provider) in LanguageModelRegistry::global(cx)
                     .read(cx)
                     .providers()
+                    .into_iter()
                     .enumerate()
                 {
                     if index > 0 {