[SYCL][Bindless] Fix allocation for exportable Vulkan interop images (#22836)
`depth_format` failed on Windows Intel GPUs not because of a SYCL/UR bug
but because the test built an invalid/mis-described `VkImage`. Three
defects, all things the passing sibling tests (`vulkan_setup.hpp`)
already do correctly:
- Under-sized allocation — memory was sized as `w*h*sizeof(float)`
instead of the driver's `VkMemoryRequirements::size`. That's smaller
than required on any GPU that pads tiled images (hard VUID violation);
hidden on BMG (zero padding), surfaced on DG2 (65536 < 73856).
- No dedicated allocation — used only when the driver reported it
required, but BMG under-reports for external memory → pool-allocated →
exported handle describes the wrong layout → SYCL reads land at wrong
offsets.
- Missing STORAGE_BIT — image was transfer-only, but the kernel accesses
it as a storage image.
**Fix**: in the shared vulkan_common.hpp, use the real
memory-requirement size and use dedicated allocation for any exportable
image; in the test, add STORAGE_BIT and thread the real size into the
SYCL import descriptor. mipmaps.cpp (the only other consumer) is
strictly more correct too.
**Result**: depth_format passeson BMG, XFAIL (#21986) removed. DG2 XFAIL
(#21985) kept — this is a driver bug, not a test issue.