upgrade emsdk to 4.0.4 (#23819)
### Description
Upgrade EMSDK to 4.0.4
### Motivation and Context
Emscripten v4.0.4 brings 2 useful changes that are helpful for webgpu:
- https://github.com/emscripten-core/emscripten/pull/23678
- https://github.com/emscripten-core/emscripten/pull/23631
