wgsl: validate parsing of sampled texture types

[dj2]

For each of the texture types {texture_1d, texture_2d, texture_2d_array, texture_3d, texture_cube, texture_cube_array, texture_multisampled_2d}

• [x] Types of f32, i32, u32 are accepted
• [x] All other types are rejected
• [ ] No type fails texture_1d and texture_1d<>
• [ ] Invalid type fails texture_1d<invalid>
• [ ] Missing < or > fails

4.6.2. Sampled Texture Types

[dj2]

https://github.com/gpuweb/cts/blob/main/src/webgpu/shader/validation/types/textures.spec.ts