Fix unused variable compilation error #1705

Job	Run time
Linux x86_64 GPU w/ cuVS packages (CUDA 11.8.0)	0s
Format	33s
Linux x86_64 (cmake)	15m 4s
Linux arm64 packages	0s
Linux x86_64 GPU w/ cuVS packages (CUDA 12.4.0)	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 GPU (cmake)	39m 39s
Linux x86_64 GPU w/ cuVS (cmake)	1h 39m 47s
Linux arm64 SVE (cmake)	14m 12s
Linux x86_64 AVX2 (cmake)	15m 29s
Linux arm64 (conda)	11m 4s
Linux x86_64 AVX512 (cmake)	21m 39s
Linux x86_64 (conda)	16m 30s
Linux x86_64 GPU w/ ROCm (cmake)	30m 26s
Windows x86_64 (conda)	17m 35s
	4h 41m 58s

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