Arm backend: Fix VKML init and env for MacOS (#18286) #20

Job	Run time
export-model-cuda-windows-artifact (mistralai, Voxtral-Mini-3B-2507, quantized-int4-weight-only) / linux-job	1s
export-model-cuda-windows-artifact (mistralai, Voxtral-Mini-3B-2507, non-quantized) / linux-job	1s
export-model-cuda-windows-artifact (nvidia, parakeet-tdt, quantized-int4-weight-only) / linux-job	1d 0h 0m 1s
export-model-cuda-windows-artifact (mistralai, Voxtral-Mini-4B-Realtime-2602, quantized-int4-tile... / linux-job	1d 0h 0m 1s
export-model-cuda-windows-artifact (nvidia, parakeet-tdt, non-quantized) / linux-job	1s
export-model-cuda-windows-artifact (nvidia, diar_streaming_sortformer_4spk-v2, non-quantized) / linux-job	1s
export-model-cuda-windows-artifact (facebook, dinov2-small-imagenet1k-1-layer, non-quantized) / linux-job	1d 0h 0m 1s
test-model-cuda-windows-e2e	0s
	3d 0h 0m 7s

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