Refactor staff mode into a seperate crate and make copilot initialization wait for the staff mode flag to be flipped

crates/theme_selector/src/theme_selector.rs

@@ -7,7 +7,7 @@ use picker::{Picker, PickerDelegate};
 use settings::{settings_file::SettingsFile, Settings};
 use std::sync::Arc;
 use theme::{Theme, ThemeMeta, ThemeRegistry};
-use util::StaffMode;
+use staff_mode::StaffMode;
 use workspace::{AppState, Workspace};
 
 pub struct ThemeSelector {