lvp/venus/ci: fix lvp immutable sampler handling and update ci expect

What does this MR do and why?

lvp/venus/ci: fix lvp immutable sampler handling and update ci expect

Lavapipe has switched to layer push descriptor support atop descriptor updates internally since 12a7fc51, so it must skip retrieving immutable samplers from the write info even if the update call itself is blessed by the spec to not hit that case.

Fixes: 12a7fc51 ("lavapipe: Rework descriptor handling")

There're 16 successful CI runs without failures or flakiness: https://gitlab.freedesktop.org/zzyiwei/mesa/-/jobs/45896963

CTS coverage follow up is here: https://gitlab.khronos.org/Tracker/vk-gl-cts/-/issues/4568