inline assistant: Fix model picker (#29136)

Release Notes:

- inline assistant: Fixed a bug where the default model would be used
even when a specific inline assistant model was configured

crates/agent/src/buffer_codegen.rs

@@ -1,7 +1,7 @@
 use crate::context::attach_context_to_message;
 use crate::context_store::ContextStore;
 use crate::inline_prompt_editor::CodegenStatus;
-use anyhow::{Context as _, Result};
+use anyhow::Result;
 use client::telemetry::Telemetry;
 use collections::HashSet;
 use editor::{Anchor, AnchorRangeExt, MultiBuffer, MultiBufferSnapshot, ToOffset as _, ToPoint};
@@ -131,7 +131,12 @@ impl BufferCodegen {
         cx.notify();
     }
 
-    pub fn start(&mut self, user_prompt: String, cx: &mut Context<Self>) -> Result<()> {
+    pub fn start(
+        &mut self,
+        primary_model: Arc<dyn LanguageModel>,
+        user_prompt: String,
+        cx: &mut Context<Self>,
+    ) -> Result<()> {
         let alternative_models = LanguageModelRegistry::read_global(cx)
             .inline_alternative_models()
             .to_vec();
@@ -155,11 +160,6 @@ impl BufferCodegen {
             }));
         }
 
-        let primary_model = LanguageModelRegistry::read_global(cx)
-            .default_model()
-            .context("no active model")?
-            .model;
-
         for (model, alternative) in iter::once(primary_model)
             .chain(alternative_models)
             .zip(&self.alternatives)