[BUG] Fix Add method in LayerTable #1484

Job	Run time
check src/dotnet	13s
check if dotnet tests changed	7s
check src/bindings	5s
check build scripts and tools	5s
check if js tests changed	7s
check if py tests changed	5s
check workflow_ci	6s
build python 3.10 linux ubuntu-latest bdist	5m 41s
build python sdist	6m 56s
build python 3.11 linux ubuntu-latest bdist	5m 43s
build python 3.12 linux ubuntu-latest bdist	5m 52s
build python 3.10 windows windows-2019 bdist	9m 2s
build python 3.11 windows windows-2019 bdist	9m 17s
build python 3.12 windows windows-2019 bdist	9m 3s
build python 3.10 macos macos-12 bdist	10m 23s
build python 3.11 macos macos-12 bdist	9m 59s
build python 3.12 macos macos-12 bdist	13m 8s
build python 3.10 macos macos-14 bdist	7m 32s
build python 3.11 macos macos-14 bdist	10m 3s
build python 3.12 macos macos-14 bdist	13m 41s
build rhino3dm.js	19m 12s
build dotnet	0s
test dotnet	0s
test py 3.10 linux ubuntu-latest bdist	7s
test py 3.11 linux ubuntu-latest bdist	7s
test py 3.12 linux ubuntu-latest bdist	6s
test py 3.10 windows windows-2019 bdist	1m 4s
test py 3.11 windows windows-2019 bdist	1m 5s
test py 3.12 windows windows-2019 bdist	1m 4s
test py 3.10 macos macos-12 bdist	15s
test py 3.11 macos macos-12 bdist	16s
test py 3.12 macos macos-12 bdist	17s
test py 3.10 macos macos-14 bdist	10s
test py 3.11 macos macos-14 bdist	12s
test py 3.12 macos macos-14 bdist	9s
test javascript	19s
	2h 21m 31s

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