support bfloat16 in python #1709

Job	Run time
Linux arm64 packages	0s
Format	30s
Linux x86_64 (cmake)	15m 6s
Linux x86_64 GPU w/ cuVS packages (CUDA 12.4.0)	0s
Linux x86_64 GPU w/ cuVS packages (CUDA 11.8.0)	0s
Linux x86_64 GPU packages (CUDA 11.4.4)	0s
Linux x86_64 GPU packages (CUDA 12.1.1)	0s
Linux x86_64 packages	0s
OSX arm64 packages	0s
Windows x86_64 packages	0s
Linux x86_64 (conda)	16m 14s
Windows x86_64 (conda)	29m 58s
Linux arm64 (conda)	11m 30s
Linux arm64 SVE (cmake)	14m 11s
Linux x86_64 AVX2 (cmake)	15m 21s
Linux x86_64 AVX512 (cmake)	20m 48s
Linux x86_64 GPU (cmake)	39m 28s
Linux x86_64 GPU w/ cuVS (cmake)	1h 39m 31s
Linux x86_64 GPU w/ ROCm (cmake)	33m 37s
	4h 56m 14s

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