assistant2: Tweak the settings UI (#23845)

This PR does some somewhat light UI adjustment to the Assistant 2
settings view. The Prompt Library section should feature the default
prompts in the future, so that's why it's been separated that way.

<img width="800" alt="Screenshot 2025-01-29 at 2 59 59 PM"
src="https://github.com/user-attachments/assets/7b033bde-51ab-44d5-9e53-3f72b8ff5f51"
/>

Release Notes:

- N/A

crates/assistant2/src/assistant_panel.rs

@@ -613,7 +613,7 @@ impl AssistantPanel {
                 })
                 .unwrap_or_else(|| SharedString::from("Loading Summary…")),
             ActiveView::History | ActiveView::PromptEditorHistory => "History".into(),
-            ActiveView::Configuration => "Configuration".into(),
+            ActiveView::Configuration => "Assistant Settings".into(),
         };
 
         let sub_title = match self.active_view {
@@ -700,7 +700,7 @@ impl AssistantPanel {
                         IconButton::new("configure-assistant", IconName::Settings)
                             .icon_size(IconSize::Small)
                             .style(ButtonStyle::Subtle)
-                            .tooltip(Tooltip::text("Configure Assistant"))
+                            .tooltip(Tooltip::text("Assistant Settings"))
                             .on_click(move |_event, window, cx| {
                                 window.dispatch_action(OpenConfiguration.boxed_clone(), cx);
                             }),