autostart scripts: Reintroduce SYS_PARAM_VER (#22813)

The case where the airframe maintainer wants to enforce a reset to airframe is
not covered anymore with the `param set-default` mechanism. For products based
on PX4 this is still required to ensure proper functionality after a major update.

src/modules/mavlink/mavlink_parameters.cpp

@@ -310,6 +310,9 @@ MavlinkParametersManager::send()
 		param_find("TRIG_MODE");
 		param_find("UAVCAN_ENABLE");
 
+		// parameter only used in startup script but should show on ground station
+		param_find("SYS_PARAM_VER");
+
 		_first_send = true;
 	}