Mark test_HSStep_NegativeBinomial_sparse_shared_y as xfail temporarily

Fix pre-commit black issue involving click requirement

Fixed bug to allow y being shared variable

Use try statement in datashader import

Add NegativeBinomial support for HSStep

Update results in notebook

Return distribution_subset_args dict instead of list

Disable flaky under/overflow constraints in test_step_methods

NumPy is raising underflow errors for `exp(-inf)` only in CI.

Use Conda environment for testing and cancel stale jobs

Increase time-varying test's sample and tuning sizes