Fix transparency (#14010)

Release Notes:

- (preview only) Fix transparent themes

crates/workspace/src/status_bar.rs

@@ -50,7 +50,11 @@ impl Render for StatusBar {
                     })
                     .when(!(tiling.bottom || tiling.left), |el| {
                         el.rounded_bl(CLIENT_SIDE_DECORATION_ROUNDING)
-                    }),
+                    })
+                    // This border is to avoid a transparent gap in the rounded corners
+                    .mb(px(-1.))
+                    .border_b(px(1.0))
+                    .border_color(cx.theme().colors().status_bar_background),
             })
             .child(self.render_left_tools(cx))
             .child(self.render_right_tools(cx))