Remove anaconda-prune yml files as these have been moved to test-infra (#94610)
Merge after https://github.com/pytorch/test-infra/pull/2691
These workflows would run from test-infra repository instead, after the PR (https://github.com/pytorch/test-infra/pull/2691) is merged.
Not deleting anaconda-prune/ scripts because they may become handy during release if there is need to delete packages (no need to find these scripts in test-infra).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94610
Approved by: https://github.com/atalman
