Update on "[11/n][ET-VK] Introduce vTensor creation from external image"

Nearly all metadata is initialized to null/dummy values, except those absolutely needed in the pipeline: (1) image extents, (2) logical limits.

Differential Revision: [D63843819](https://our.internmc.facebook.com/intern/diff/D63843819/)

[ghstack-poisoned]

Author: jorgep31415