trunk/56a6a6c7510ef763dbc1b7f43c5ac75429416def: Revert "[DTensor] avoid P(sum) propagation on L0-norm (#174617)"

PyTorch's automated bot reverted a recent change to its DTensor system that aimed to avoid unnecessary sum propagation on L0-norm calculations. The commit, #174617, was automatically rolled back to prevent unspecified problematic behavior, as flagged in the project's internal tracking. This highlights the continuous, automated quality control in major open-source frameworks where even subtle tensor operation changes can have cascading effects on distributed machine learning workloads.