fix(ui): update ext_ui widgets when attaching non-remote UI

Problem:  Updating internalized UI capabilities is postponed until a
          remote UI attaches.
Solution: Always update active UI widgets in ui_refresh().

src/nvim/ui.c

@@ -194,15 +194,6 @@ void ui_refresh(void)
     abort();
   }
 
-  if (!ui_active()) {
-    return;
-  }
-
-  if (updating_screen) {
-    ui_schedule_refresh();
-    return;
-  }
-
   int width = INT_MAX;
   int height = INT_MAX;
   bool ext_widgets[kUIExtCount];
@@ -234,11 +225,19 @@ void ui_refresh(void)
     }
     ui_ext[i] = ext_widgets[i];
     if (i < kUIGlobalCount) {
-      ui_call_option_set(cstr_as_string(ui_ext_names[i]),
+      ui_call_option_set(cstr_as_string(ui_ext_names[i]), BOOLEAN_OBJ(ext_widgets[i]));
-                         BOOLEAN_OBJ(ext_widgets[i]));
     }
   }
 
+  if (!ui_active()) {
+    return;
+  }
+
+  if (updating_screen) {
+    ui_schedule_refresh();
+    return;
+  }
+
   ui_default_colors_set();
 
   int save_p_lz = p_lz;

test/functional/lua/ui_event_spec.lua

@@ -155,6 +155,14 @@ describe('vim.ui_attach', function()
       },
     }, actual, vim.inspect(actual))
   end)
+
+  it('ui_refresh() works without remote UI', function()
+    screen:detach()
+    exec_lua('vim.ui_attach(ns, { ext_messages = true }, on_event)')
+    n.api.nvim_set_option_value('cmdheight', 1, {})
+    screen:attach()
+    eq(1, n.api.nvim_get_option_value('cmdheight', {}))
+  end)
 end)
 
 describe('vim.ui_attach', function()