[sparsity][refactor] Remove "Sparsity" from the function names (#56555)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56555
Remove the "sparse" and "sparsity" from the function/variable names
Test Plan: `buck test mode/opt //caffe2/torch/fb/model_optimization:sparsity_test`
Reviewed By: raghuramank100
Differential Revision: D27812205
fbshipit-source-id: 1665253720467030b84b744f824fa7742a802542
