Resolves issue with nearest filtering on UI Icons. Note that as
Metal does not support LOD bias as a parameter on a sampler
object, the original code has been modified to perform LOD
biasing at the shader level.
As GPU_SAMPLER_ICON is not widely used, it is more
efficient to apply directly to the affected shaders, rather
than workaround passing in the sampler LOD bias as a
separate value e.g. uniform or push constant.
Original PR feedback addressed to also refactor ICON
shaders to use consistent style for single and multi
Icon rendering.
Authored by Apple: Michael Parkin-White
Ref #96261
Pull Request #105145
