fix: Add toggle theme as standard dropdown option

- For new sites toggle theme was not available. It was added via patch for old sites.

frappe/utils/install.py

@@ -219,6 +219,12 @@ def add_standard_navbar_items():
 			'action': 'frappe.ui.toolbar.toggle_full_width()',
 			'is_standard': 1
 		},
+		{
+			'item_label': 'Toggle Theme',
+			'item_type': 'Action',
+			'action': 'new frappe.ui.ThemeSwitcher().show()',
+			'is_standard': 1
+		},
 		{
 			'item_label': 'Background Jobs',
 			'item_type': 'Route',