TestGpuNnapi: add missing sType for VkExternalBufferProperties am: ff83e506bf am: ccb58e838d am: 87b072dd47

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NeuralNetworks/+/2308100

Change-Id: I3ff7fe7b07f859d631a92fdb63cf9f8effc77005
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>