fix: install add_cpp_mock_scenario_test.cmake first, or colcon build won't pass

[XiaoyuWang0601]

Description

This PR follows with fix/colcon_build_error.

Abstract

There is an error in some environments due to forgetting to write install.

Background

N/A

Details

With a brand new workspace, add_cpp_mock_scenario_test.cmake needs to be installed in CMakeLists.txt first. Or you will have the error below:

CMake Error at /path_to_workspace/install/cpp_mock_scenarios/share/cpp_mock_scenarios/cmake/cpp_mock_scenarios_ament_cmake-extras.cmake:17 (include):
  include could not find requested file:
/path_to_workspace/install/cpp_mock_scenarios/share/cpp_mock_scenarios/cmake/add_cpp_mock_scenario_test.cmake

References

N/A

Destructive Changes

N/A

Known Limitations

N/A

[github-actions]

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