Change zed.dev's default model to Claude 3.7 Sonnet (#28541)

From Claude 3.5 Sonnet to **Claude 3.7 Sonnet**.

Release Notes:

- Change the default model of Zed's hosted LLM service to Claude 3.7
Sonnet.

crates/assistant_settings/src/assistant_settings.rs

@@ -742,7 +742,7 @@ mod tests {
                 AssistantSettings::get_global(cx).default_model,
                 LanguageModelSelection {
                     provider: "zed.dev".into(),
-                    model: "claude-3-5-sonnet-latest".into(),
+                    model: "claude-3-7-sonnet-latest".into(),
                 }
             );
         });