Small fixes for JS packaging and copying #244

Job	Run time
build (python, macos-latest)	43s
build (cpp, macos-latest)	1m 22s
build (python, ubuntu-latest)	39s
build (cpp, ubuntu-latest)	1m 18s
build (jupyter, macos-latest)	1m 45s
build (js, ubuntu-latest)	1m 2s
build (rust, macos-latest)	6m 30s
build (jupyter, ubuntu-latest)	1m 58s
build (rust, ubuntu-latest)	5m 34s
build (rustjswasm, ubuntu-latest)	7m 47s
build (js, macos-latest)	1m 16s
build (rustjswasm, macos-latest)	9m 11s
build (cppjswasm, ubuntu-latest)	2m 15s
build (cppjswasm, macos-latest)	2m 13s
	43m 33s

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