Fix gazebo_sitl_multiple_run.sh scripting (#16340)

This commit fixes the problem when using scripting options. This regression was introduced by #15463

Tools/gazebo_sitl_multiple_run.sh

@@ -17,7 +17,7 @@ function spawn_model() {
 	N=$2 #Instance Number
 
 	SUPPORTED_MODELS=("iris" "iris_rtps" "plane" "standard_vtol" "rover" "r1_rover" "typhoon_h480")
-	if [[ " ${SUPPORTED_MODELS[*]} " != *"$MODEL "* ]];
+	if [[ " ${SUPPORTED_MODELS[*]} " != *"$MODEL"* ]];
 	then
 		echo "ERROR: Currently only vehicle model $MODEL is not supported!"
 		echo "       Supported Models: [${SUPPORTED_MODELS[@]}]"