Update on "[ET-VK] 1/n Split dispatches between multiple command buffers. Add semaphore support in command buffer."

execute stage
## Context

This following diffs aims to improve the performance of the Executorch Vulkan backend by adding a mechanism to issue multiple command buffers in prepack and execute function, so GPU work is issues while CPU is still working on issuing new work.

## This Diff

### Summary

This diff is the first in a series of diffs that aim to split dispatches between multiple command buffers and add semaphore support in the command buffer.

The changes in this diff include:

*   Adding a `VkSemaphore` parameter to the `CommandBuffer` constructor in `vk_api/Command.cpp` and `vk_api/Command.h` to support signaling when the command buffer has completed execution.
*   Modifying the `CommandBuffer` constructor in `vk_api/Command.h` and `vk_api/Command.cpp` to include the `VkSemaphore` parameter.
*   Updating the `CommandBuffer` object in `api/Context.cpp` to include the `VkSemaphore` parameter.

Differential Revision: [D78282194](https://our.internmc.facebook.com/intern/diff/D78282194/)

[ghstack-poisoned]

Author: trivedivivek