Mjcf : Fix parsing of armature parameters #73

Job	Run time
ubuntu-latest - Env all Release	39m 50s
ubuntu-latest - Env all Debug	40m 57s
ubuntu-latest - Env all-py39 Release	2m 55s
ubuntu-latest - Env all-py39 Debug	4m 13s
macos-latest - Env all Release	1m 49s
macos-latest - Env all Debug	3m 36s
macos-latest - Env all-py39 Release	34m 11s
macos-latest - Env all-py39 Debug	17m 20s
macos-13 - Env all Release	54m 36s
macos-13 - Env all Debug	5m 36s
macos-13 - Env all-py39 Release	4m 14s
macos-13 - Env all-py39 Debug	46m 6s
windows-latest - Env all Release	1h 16m 32s
windows-latest - Env all-clang-cl Release	5m 22s
check-macos-linux-windows-pixi	2s
	5h 37m 19s

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