zink: track min_samples state for per sample shading

zink: track min_samples state for per sample shading

Vulkan pipeline state sampleShadingEnable and minSampleShading are directly related to GL_SAMPLE_SHADING_ARB.
Track min_samples provided by st and include it in pipeline state.
This was seen as failures in cts cases where per sample shading along with sample interpolation qualifiers are tested:
dEQP-GL45-ES31.functional.shaders.multisample_interpolation.sample_qualifier.*

Cc: mesa-stable
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18314>