Remove small code duplication in CMakelists.txt for ROS2/Ament packaging #233

Job	Run time
ubuntu-latest - Env all Release	30s
ubuntu-latest - Env all Debug	31s
ubuntu-latest - Env all-py39 Release	25s
ubuntu-latest - Env all-py39 Debug	32s
macos-latest - Env all Release	37s
macos-latest - Env all Debug	26s
macos-latest - Env all-py39 Release	22s
macos-latest - Env all-py39 Debug	23s
macos-13 - Env all Release	50s
macos-13 - Env all Debug	45s
macos-13 - Env all-py39 Release	39s
macos-13 - Env all-py39 Debug	48s
windows-latest - Env all Release	29s
windows-latest - Env all-clang-cl Release	38s
check-macos-linux-windows-pixi	2s
	7m 57s

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