CI: on mavros failure restart it instead of killing test

test/mavros_posix_tests_missions.test

@@ -11,6 +11,7 @@
         <arg name="vehicle" value="standard_vtol"/>
         <arg name="est" value="$(arg est)"/>
         <arg name="respawn_gazebo" value="$(arg respawn_gazebo)"/>
+        <arg name="respawn_mavros" value="true"/>
     </include>
     <!-- ROStest -->
     <test test-name="multicopter_box" pkg="px4" type="mission_test.py" time-limit="300.0" args="multirotor_box.plan"/>