Fix: Conditionally install launch directory if it exists (#3191)

Author: filippo-bosi

moveit_setup_assistant/moveit_setup_framework/templates/CMakeLists.txt

@@ -5,9 +5,12 @@ find_package(ament_cmake REQUIRED)
 
 ament_package()
 
-install(
-  DIRECTORY launch
-  DESTINATION share/${PROJECT_NAME}
-  PATTERN "setup_assistant.launch" EXCLUDE)
+if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/launch")
+  install(
+    DIRECTORY launch
+    DESTINATION share/${PROJECT_NAME}
+    PATTERN "setup_assistant.launch" EXCLUDE)
+endif()
+
 install(DIRECTORY config DESTINATION share/${PROJECT_NAME})
 install(FILES .setup_assistant DESTINATION share/${PROJECT_NAME})