[webgpu] Apply template to `MatMulNBitsWideTile` (#25353)
### Description
This commit applies WGSL template to `MatMulNBitsWideTile` to improve
code readability and enables more flexible data handling.
As part of this change, support for 4-bit and 8-bit shaders has been
consolidated, and a common `CEIL_DIV` utility has been introduced. The
previous `ShaderUsage::UseUniform` and
`ShaderUsage::UseIndicesTypeAlias` flags are no longer necessary and
have been removed.
### Motivation and Context
See above
