[BugFix] Make VecNorm Transform pickable #7714

Job	Run time
build-wheel-mac (3.8, 3.8)	2m 12s
build-wheel-linux (3.8, cp38-cp38, --extra-index-url https://download.pytorch.org/whl/cpu, "['cpu...	1m 59s
build-wheel-mac (3.9, 3.9)	1m 57s
build-wheel-mac (3.10, 3.10.3)	1m 52s
build-wheel-linux (3.9, cp39-cp39, --extra-index-url https://download.pytorch.org/whl/cpu, "['cpu...	2m 24s
build-wheel-mac (3.11, 3.11)	10m 2s
build-wheel-linux (3.10, cp310-cp310, --extra-index-url https://download.pytorch.org/whl/cpu, "['...	2m 31s
build-wheel-windows (3.8, 3.8)	3m 46s
build-wheel-linux (3.11, cp311-cp311, --extra-index-url https://download.pytorch.org/whl/cpu, "['...	2m 32s
build-wheel-windows (3.9, 3.9)	3m 23s
build-wheel-windows (3.10, 3.10.3)	5m 14s
build-wheel-windows (3.11, 3.11)	3m 25s
test-wheel-windows (3.8)	5m 16s
test-wheel-windows (3.9)	8m 23s
test-wheel-windows (3.10)	6m 38s
test-wheel-windows (3.11)	8m 0s
test-wheel (linux, ubuntu-20.04, 3.8)	3m 13s
test-wheel (linux, ubuntu-20.04, 3.9)	3m 18s
test-wheel (linux, ubuntu-20.04, 3.10)	3m 20s
test-wheel (linux, ubuntu-20.04, 3.11)	4m 3s
test-wheel (mac, macos-latest, 3.8)	4m 58s
test-wheel (mac, macos-latest, 3.9)	3m 12s
test-wheel (mac, macos-latest, 3.10)	5m 16s
test-wheel (mac, macos-latest, 3.11)	3m 28s
	1h 40m 22s

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