Update on "[ET-VK][Ops] common test utils for converting aten types to vulkan types"

most custom ops utilize some aten to executorch scalartype conversion. this test file standardized that across those files

Differential Revision: [D76464550](https://our.internmc.facebook.com/intern/diff/D76464550/)

cc SS-JIA manuelcandales cbilgin

[ghstack-poisoned]

Author: morelos