* Introduce SamplerBindingType enum and fix bug in validation
This matches the WebGPU spec more closely and also lets us implement the
validation as it's written in the spec[1]. This fixes a bug which
previously prevented the "shadow" example from running in Firefox.
Previously the validation would check whether the filtering was
appropiate even if it was a comparison sampler. This didn't matter when
running the shadow example natively since the example was setting
`filtering: true` in addition to `comparison: true`. But this failed
when running through a browser since there the used WebIDL has the
proper enum representation and eventually resulted in `filtering: false`
being passed to wgpu-core which would then fail validation.[2]
[1]: https://gpuweb.github.io/gpuweb/#bind-group-creation
[2]: 674b6582ba/dom/webgpu/ipc/WebGPUChild.cpp (L502-L513)
* Fix remaining examples
* Fix deno_webgpu
