Refine status bar design (#34324)

Experimenting with a set of standardized icons and polishing spacing a
little bit.

Release Notes:

- N/A

crates/terminal_view/src/terminal_panel.rs

@@ -1437,7 +1437,7 @@ impl Panel for TerminalPanel {
         if (self.is_enabled(cx) || !self.has_no_terminals(cx))
             && TerminalSettings::get_global(cx).button
         {
-            Some(IconName::Terminal)
+            Some(IconName::TerminalAlt)
         } else {
             None
         }