Drop redundant ART megatron extra

Author: Kovbo

pyproject.toml

@@ -41,20 +41,6 @@ backend = [
     "nvidia-cudnn-frontend<1.21 ; sys_platform == 'linux'",
     "vllm @ https://github.com/vivekkalyan/vllm/releases/download/v0.17.0-art1/vllm-0.17.0%2Bart1-cp38-abi3-manylinux_2_31_x86_64.whl ; sys_platform == 'linux'",
 ]
-megatron = [
-    "torch>=2.8.0",
-    "quack-kernels==0.2.5",
-    "apex",
-    "transformer-engine==2.11.0",
-    "transformer-engine-cu12==2.11.0",
-    "transformer-engine-torch==2.11.0",
-    "megatron-core==0.16.0rc0",
-    "pybind11>=2.13.6",
-    "megatron-bridge",
-    "nvidia-ml-py==13.580.82",
-    "ml-dtypes>=0.5.0 ; python_full_version < '3.13'",
-]
-
 langgraph = [
     "langchain-core>=0.3.51",
     "langgraph>=0.6.2",