Update on "[ET-VK] Add Vulkan backend support for Parakeet runner and export"

Add Vulkan build support for the Parakeet runner: llm-debug-vulkan preset
in root CMakePresets.json, parakeet-vulkan presets in the Parakeet
CMakePresets.json, vulkan_backend linkage in CMakeLists.txt, and a
`make parakeet-vulkan` Makefile target.

Add _create_vulkan_partitioners() and wire it into lower_to_executorch()
so that `--backend vulkan` is accepted by export_parakeet_tdt.py.

Differential Revision: [D95970157](https://our.internmc.facebook.com/intern/diff/D95970157/)

cc manuelcandales digantdesai cbilgin

[ghstack-poisoned]

Author: ssjia