Show update spinner by default in dev_build=yes editor builds

This ensures contributors can see when something forces the
editor to redraw constantly.

The existing boolean `true` value will be casted to `1` in the setting,
so it'll switch to Enabled automatically if the setting was previously
enabled.

editor/editor_node.h

@@ -488,6 +488,8 @@ private:
 
 	String _get_system_info() const;
 
+	bool _should_display_update_spinner() const;
+
 	static void _dependency_error_report(const String &p_path, const String &p_dep, const String &p_type) {
 		DEV_ASSERT(Thread::get_caller_id() == Thread::get_main_id());
 		if (!singleton->dependency_errors.has(p_path)) {