[webgpu] Remove `global_id` and `workgroup_id` in gemm_utils.cc (#26662)
### Description
This patch replaces `global_id` and `workgroup_id` with
`logical_global_id` and `logical_workgroup_id` which are computed from
`workgroup_idx` and the dispatch workgroup sizes set in
`ProgramBase::SetDispatchGroupSize()`.
### Motivation and Context
We shouldn't use `global_id` or `workgroup_id` directly because the
dispatch workgroup sizes may be normalized in
`ProgramManager::NormalizeDispatchGroupSize()`.