Update on "[ET-VK] Shortening code for slice op when packed dim is not the same as slice dim."

This diff is a code change for the Slice op to shorten its code when packed dimension is not the same as the slice dimension.

Differential Revision: [D70737264](https://our.internmc.facebook.com/intern/diff/D70737264/)

[ghstack-poisoned]

Author: trivedivivek