[Fix] Remove redundant allreduce fusion block and skip TP=1#20621

Fridge003 merged 7 commits intosgl-project:mainsgl-project/sglang:mainfrom

mmangkad-dev:fix-allreduce-fusion-tp1-redundancymmangkad-dev/sglang:fix-allreduce-fusion-tp1-redundancyCopy head branch name to clipboard