Fix interactive shell with roslaunch (#14919)

Fixes the interactive shell that was not working previously when starting px4 sitl with roslaunch

launch/px4.launch

@@ -11,8 +11,8 @@
 
     <env name="PX4_SIM_MODEL" value="$(arg vehicle)" />
     <env name="PX4_ESTIMATOR" value="$(arg est)" />
-    <arg unless="$(arg interactive)" name="px4_command_arg1" value=""/>
-    <arg     if="$(arg interactive)" name="px4_command_arg1" value="-d"/>
+    <arg unless="$(arg interactive)" name="px4_command_arg1" value="-d"/>
+    <arg     if="$(arg interactive)" name="px4_command_arg1" value=""/>
     <node name="sitl_$(arg ID)" pkg="px4" type="px4" output="screen" args="$(find px4)/ROMFS/px4fmu_common -s etc/init.d-posix/rcS -i $(arg ID) $(arg px4_command_arg1)">
     </node>
 </launch>