Add setting to show/hide title bar (#37428)

Closes #5120

Release Notes:

- Added settings for hiding and showing title bar



https://github.com/user-attachments/assets/aaed52d0-6278-4544-8932-c6bab531512a

crates/workspace/src/workspace.rs

@@ -2043,6 +2043,11 @@ impl Workspace {
         cx.notify();
     }
 
+    pub fn clear_titlebar_item(&mut self, _: &mut Window, cx: &mut Context<Self>) {
+        self.titlebar_item = None;
+        cx.notify();
+    }
+
     pub fn set_prompt_for_new_path(&mut self, prompt: PromptForNewPath) {
         self.on_prompt_for_new_path = Some(prompt)
     }