[modular] speedup check_modular_conversion with multiprocessing (#37456)
* Change topological sort to return level-based output (lists of lists)
* Update main for modular converter
* Update test
* update check_modular_conversion
* Update gitignore
* Fix missing conversion for glm4
* Update
* Fix error msg
* Fixup
* fix docstring
* update docs
* Add comment
* delete qwen3_moe