Remove Clang && Vulkan XFAIL from Feature/CBuffer/array-dynamic-index.test

[Icohedron]

This PR removes the Clang && Vulkan XFAIL from Feature/CBuffer/array-dynamic-index.test since the test now XPASSes on all runners:

╭───┬──────────────────────┬─────────────┬─────────────────────────────┬────────┬──────────────────────────────────────────╮
│ # │      timestamp       │   run-id    │          workflow           │ status │                   test                   │
├───┼──────────────────────┼─────────────┼─────────────────────────────┼────────┼──────────────────────────────────────────┤
│ 0 │ 2025-11-28T12:08:27Z │ 19763375140 │ Windows Vulkan AMD Clang    │ XPASS  │ Feature/CBuffer/array-dynamic-index.test │
│ 1 │ 2025-11-28T18:05:22Z │ 19771042891 │ Windows Vulkan Intel Clang  │ XPASS  │ Feature/CBuffer/array-dynamic-index.test │
│ 2 │ 2025-11-28T04:03:18Z │ 19753735507 │ Windows Vulkan NVIDIA Clang │ XPASS  │ Feature/CBuffer/array-dynamic-index.test │
│ 3 │ 2025-11-28T18:09:04Z │ 19771107957 │ Windows Vulkan QC Clang     │ XPASS  │ Feature/CBuffer/array-dynamic-index.test │
╰───┴──────────────────────┴─────────────┴─────────────────────────────┴────────┴──────────────────────────────────────────╯

• Windows Vulkan AMD Clang
• Windows Vulkan Intel Clang
• Windows Vulkan NVIDIA Clang
• Windows Vulkan QC Clang

Before merging this PR, check/update the status of the original issue associated with the XFAIL: llvm/llvm-project#159602

[s-perron]

That seems right. I just merged some fixed for cbuffers yesterday.