Update on "[ET-VK] Tuning local workgroup size calculation for conv2d pw to improve performance."

This diff adjusts the local workgroup size (`local_wg_size`) based on batch count (stored in  `wg_size[1]`), to improve conv2d pw performance.

* If `wg_size[1]` is a multiple of 8, `local_wg_size_y` is set to 8.
* If `wg_size[1]` is a multiple of 4, `local_wg_size_y` is set to 4.
* If `wg_size[1]` is a multiple of 2, `local_wg_size_y` is set to 2.
* Otherwise, we default to `local_wg_size_y` = 1.

The dispatch size in 2 dimensions is then calculate based on `{64 / local_wg_size_y, local_wg_size_y, 1}`.

Differential Revision: [D75420517](https://our.internmc.facebook.com/intern/diff/D75420517/)

[ghstack-poisoned]

Author: trivedivivek